Masters Degrees (Geography and Environmental Studies)

Decision tree development for land cover classification in the Eastern Cape

2017-05-10T09:34:34Z

Decision tree development for land cover classification in the Eastern Cape Verhulp, Julie Katherine ENGLISH ABSTRACT: The purpose of this study was to develop a cost-effective and practical method for producing land cover maps by assessing the efficacy of classifier extension in a highly heterogeneous area. Effective classifier extension would reduce the amount of training data required. The high costs and excessive time taken for the collection of such data would therefore also be reduced. The highly heterogeneous Eastern Cape Province in South Africa was selected as the area of interest. Landsat-8 imagery from both the spring and summer season was acquired, and two experiments were carried out. The first experiment analysed the spectral separability of four Landsat-8 scenes in the study area. By using training data for eight land cover classes, the spectral separability for each individual scene, and that of a two-, three- and four-scene mosaic, was calculated. Tests were successfully repeated for each season and for a two-season composite. The results indicated that, while the separability of certain land cover classes decreased with the addition of more scenes, the overall separability remained constant. Further results revealed a better spectral separability from the two seasons composite compared to that of each individual season. Most classes were sufficiently separable in all scenes. The aim of the second experiment was to develop a transferable decision tree (DT) ruleset. A randomised sampling allowed for the selection of various points from the polygon training samples. Information on the pixel values of the bands, various indices, textures and elevation data was extracted for each point. A DT was developed from the dataset using the classification and regression trees (CART) algorithm. The DT was pruned and the rules applied to the four Landsat-8 and the two adjacent scenes. The four Landsat-8 scenes achieved an accuracy of 80.6%, and the two adjacent scenes 83.7% and 64.1%. The poor results of the second adjacent scene were attributed to large discrepancies in vegetation between the wet and dry seasons, causing confusion for certain classes. The inclusion of a vegetation mask elevated the accuracy of the classification to 70.4%. This research has shown that it is possible to develop a DT to accurately classify land cover in a large heterogeneous area, but that the complexity of the area can have a detrimental effect on accuracy. Additionally, it is evident that despite sufficient spectral separability, classifier; AFRIKAANS OPSOMMING: Die doel van hierdie studie was om 'n koste-effektiewe en praktiese metode vir die vervaardiging van grondbedekking kaarte te ontwikkel deur die effektiwiteit van klassifiseerder-uitbreiding in 'n hoogs heterogene area te bepaal. Effektiewe klassifiseerderuitbreiding sal die hoeveelheid opleidingdata wat benodig word verminder. Die hoë koste en oormatige tyd wat dit neem om sulke inligting in te samel sal dus ook verminder word. Die hoogs heterogene Oos-Kaap Provinsie in Suid-Afrika is gekies as die area van belang. Landsat-8 beelde van beide die lente en somer is verkry en twee eksperimente is uitgevoer. Die eerste eksperiment het die spektrale skeibaarheid van vier Landsat-8 beelde in die studiearea ontleed. Deur gebruik te maak van die opleidingsdata van agt grondbedekkingsklasse, is die spektrale skeibaarheid vir elke individuele beeld asook 'n twee-, drie-, en vier-toneel mosaïek bereken. Toetse is suksesvol herhaal vir elke seisoen, en vir 'n twee-seisoensamestelling. Die resultate dui daarop dat, alhoewel die skeibaarheid van sekere grondbedekkingsklasse met die toevoeging van meer tonele afgeneem het, die algehele skeibaarheid konstant gebly het. Verdere resultate het gedui op 'n beter spektrale skeibaarheid van die twee-seisoen-samestelling as vir elk van die individuele seisoene. Die meeste klasse het voldoende skeibaarheid in alle tonele getoon. Die doel van die tweede eksperiment was om 'n stel oordraagbare besluitnemingskemareëls (“decision tree rulesets”) te ontwikkel. 'n Ewekansige steekproefneming het die keuse van verskeie punte op die veelhoekige opleidingsmonsters toegelaat. Inligting oor die beeldelementwaardes van die bande, verskeie indekse, teksture en hoogte-data van elke punt is bekom. 'n Besluitnemingskema is ontwikkel deur 'n klassifikasie-en-regressieskema- (CART)-algoritme toe te pas. Die besluitnemingskema is gesnoei en die reëls is op die vier Landsat-8 tonele en die twee aangrensende tonele toegepas. Die vier Landsat-8 tonele het 'n akkuraatheid van 80.6% bekom, terwyl die twee aangrensende tonele onderskeidelik 83.7% en 64.1% behaal het. Die swak resultate van die tweede aangrensende toneel is toegeskryf aan groot kontraste tussen die plantegroei van die nat en droë seisoene, wat verwarring vir sekere klasse veroorsaak het. Die toepassing van 'n plantegroeimasker het die akkuraatheid van die klassifikasie na 70.4% verhoog. Hierdie navorsing toon dat dit moontlik is om 'n besluitnemingskema te ontwikkel om grondbedekking in 'n groot heterogene omgewing akkuraat te klassifiseer, maar dat die Stellenbosch University https://scholar.sun.ac.za vi kompleksiteit van die area die akkuraatheid nadelig kan beïnvloed. Verder is dit duidelik dat, ten spyte van voldoende spektrale skeibaarheid, klassifiseerder-uitbreiding via besluitnemingskemas onbetroubaar is en dat deskundige reëls of addisionele GIS data benodig mag word om oordraagbaarheid te verbeter. Thesis (MSc)--Stellenbosch University, 2017.

Indirect soil salinity detection in irregated areas using earth observation methods

2017-05-10T10:50:40Z

Indirect soil salinity detection in irregated areas using earth observation methods Muller, Sybrand Jacobus ENGLISH ABSTRACT: Excessive accumulation of salt in the plant root zone has a deteriorating effect on vegetation growth, resulting in reduced crop yield and rendering fertile soil barren, and ultimately leads to decreasing food production. This problem motivates the critical need for active salinity monitoring, with an aim to implement rehabilitation and preventive measures. Conventional salinity monitoring methods, such as regular field visits and laboratory analyses of soil samples, are ineffective for frequent salt accumulation monitoring over large areas. Earth observation techniques can complement conventional methods and potentially improve the cost- and time-efficiency of the regular salt accumulation monitoring. A review of literature identified a number of direct and indirect approaches for detecting accumulated salts using remote sensing. Given that salt accumulation in South Africa is most prevalent in irrigation schemes, the indirect approach, which mainly focusses on salt induced vegetation response, was identified as the preferred approach. Little is known about the optimal combinations of very high resolution satellite imagery and image classification techniques in South African irrigation schemes, where accumulated salt generally occurs in small localized patches. Consequently, two experiments were carried out to: identify suitable spectral and spatial resolutions of imagery; test the value of various image-derived features and classification techniques; and evaluate the spatial scale at which salt accumulation is best identified. The first experiment, applied on an agricultural field scale, analysed WorldView-2 imagery with statistical (regression) and machine learning (decision trees) techniques, and found clear relationships between salt accumulation and image transformations (vegetation indices and image texture). Spatial resolutions of six metres or higher were found to be most suitable. A higher spectral resolution marginally improved classification accuracies, but the increases were insignificant. The second experiment, applied on an irrigation scheme level, assessed SPOT-5 imagery with statistical (regression) and machine learning (various algorithms) techniques in two irrigation schemes. The failure to highlight any consistent image transformation or classification techniques for both irrigation schemes emphasised the negative effect of varying salinity tolerances of crop types and growing phases in identifying salt accumulation. Knowledge gained from the two experiments aided the development of a field level object-based monitoring system that showed sufficient transferability. The quantitative experiments answered key research questions and will serve as a point of departure for future research regarding indirect methods for detecting salt accumulation in agricultural fields. This work will be instrumental in the establishment of a South African salinity monitoring system – with the aim of rehabilitation – and will help to maximize agricultural production and ultimately contribute to sustainable food production.; AFRIKAANS OPSOMMING: ’n Oormaat sout in ’n plant se wortelarea het ’n nadelige effek op die plant se groei, veroorsaak ’n afname in oesopbrengs en maak vrugbare grond onvrugbaar, wat uiteindelik tot ’n afname in voedselproduksie lei. Hierdie probleem motiveer die kritiese behoefte aan ’n stelsel wat grondversouting aktief moniteer, met die doel om versoute areas te rehabiliteer en te voorkom. Tradisionele metodes om grondversouting te moniteer sluit gereelde veldwerk en laboratoriumontleding van grondmonsters in, maar is nie vir die gereelde monitering van groot grondversoute-areas effektief nie. Afstandswaarnemingmetodes kan konvensionele metodes aanvul en moontlik tot ’n afname in die tyd en koste verbonde aan die gereelde montering van soutophoping lei. ’n Literatuuroorsig het direkte en indirekte metodes vir die identifisering van grondversouting met behulp van afstandswaarneming uitgelig. Aangesien grondversouting in Suid-Afrika grootliks in besproeiingskemas voorkom, word die indirekte metode, wat die afname in plantegroei as gevolg van grondversouting monitor, verkies. Min inligting is beskikbaar oor die optimale kombinasies van baie hoë resolusie satellietbeelde en beeldklassifikasie-metodes in Suid-Afrikaanse besproeiingskemas, waar grondversouting in klein, gelokaliseerde areas voorkom. Gevolglik is twee eksperimente uitgevoer om geskikte spektrale en ruimtelike resolusies te identifiseer; kenmerke afgelei van beelde en beeldklassifikasie-tegnieke te toets; en die mees geskikte ruimtelike skaal vir die identifisering van grondversouting te evalueer. Die eerste eksperiment, toegepas op ŉ landeryskaal, het WoldView-2 beeldmateriaal met statistiese (regressie) en masjienleer- (beslissingsboom) metodes geanaliseer en het gevind dat daar duidelike verhoudings tussen grondversouting en beeldtransformasies (plantegroeiindeks en beeldtekstuur) bestaan. Ruimtelike resolusies as ses meter of kleiner was as aanvaarbaar beskou. ’n Hoër spektrale resolusie het die resultate effens verbeter, maar was nie betekenisvol nie. Die tweede eksperiment, wat op ’n skema-vlak toegepas was, het SPOT-5-beeldmateriaal met statistiese (regressie) en masjienleermetodes (verskeidenheid algoritmes) op twee verskillende besproeiingskemas geëvalueer. Geen konsekwente beeldtransformasies of -klassifikasies vir die twee studieareas kon uitgelig word nie, wat op die negatiewe effek van die wisselende versoutingstoleransies en verskillende groeistadiums van die gewasse dui. Die kennis wat deur die twee eksperimente opgedoen is, het gelei tot die ontwikkeling van ’n objekgebaseerde-moniteringsisteem op landeryskaal wat voldoende oordraagbaarheid getoon het. Die kwantitatiewe eksperimente het kernnavorsingsvrae beantwoord en sal as ’n vertrekpunt dien vir enige toekomstige navorsing oor die gebruik van indirekte afstandswaarneming metodes vir die identifisering van grondversouting. Die navorsing sal ook bydra tot die vestiging van ’n Suid- Afrikaanse grondversoutingmoniteringsisteem – met die oog op rehabilitasie – wat tot die maksimalisering van landbouproduksie en uiteindelik tot volhoubare voedselproduksie kan lei. Thesis (MSc)--Stellenbosch University, 2017.

Scaling patterns and drivers of species richness and turnover across the Afrotropics

2017-05-05T14:27:02Z

Scaling patterns and drivers of species richness and turnover across the Afrotropics Bailey, Junior Curtis ENGLISH ABSTRACT: Understanding the broad scale patterns and environmental determinants of amphibian richness (α-diversity) and turnover (β-diversity) is becoming ever more crucial as communities, ecosystems and landscapes are increasingly threatened by anthropogenic processes and climate change. Spatial scale, the grain at which sampling takes place or analysis occurs, confounds understanding of such diversity patterns and the relationships these exhibit with environmental processes. This is because various processes operate at different spatial scales resulting in different patterns emerging at different spatial scales. This is problematic, because patterns, and pattern-process’ relationships which emerge at one scale may not hold at another scale thereby confounding our understanding of how biotic patterns are generated and maintained, thus leading to misguided conservation strategies and policies. The focus of the present study was thus to examine the relationship between present patterns of anuran richness and turnover, the relationship of these with several contemporary environmental processes, and how these patterns and pattern-process relationships are influenced by spatial grain. Using IUCN range data for the Afrotropical region, amphibian richness and turnover patterns were generated using a Geographic Information System and quantified using the recently formulated zeta diversity partitioning method (ζ). These patterns were then related to several contemporary environmental variables/processes hypothesised to govern amphibian diversity across a range of spatial scales using both the global Ordinary Least Squares (OLS) method and local spatial Geographically Weighted Regression (GWR) across three nested spatial grains. The results show that amphibian richness and turnover patterns (visual & empirical) and the relationships these exhibit with environmental conditions were sensitive to spatial grain. Visually, spatial patterns were more distinct at finer grains, but visibly smooth at the coarser grains. The statistics describing these patterns suggest that the scaling behaviour follows an increasing linear and nonlinear trend across spatial grain. Results from both the OLS and GWR models confirm that contemporary environmental conditions are significant determinants of both anuran richness and turnover patterns across spatial grain. Precipitation was the strongest determinant of anuran richness while topographic complexity best explained turnover. The relationship between both diversity components and environmental conditions, however, was scale dependent with environmental conditions explaining a greater proportion of the variation in these biotic patterns at coarser than finer grains. Studies conducted across multiple grains is thus recommended to improve current understanding of biodiversity patterns and the relationship they exhibit with environmental processes.; AFRIKAANS OPSOMMING: Dit word al hoe meer noodsaaklik om die grootskaalse patrone en omgewingsdeterminante van amfibiese rykdom (α-diversiteit) en omset (β-diversiteit) te verstaan soos gemeenskappe, ekosisteme en landskappe bedreig word deur mensgemaakte prosesse en klimaatsverandering. Ruimetelike skaal, die grein waarteen monstering of analise plaasvind, verydel die begrip van sulke diversiteitspatrone en die verwantskappe wat vertoon word met omgewingsprosesse. Dit is omdat verskillende prosesse teen verskillende ruimtelike skale funksioneer wat daartoe lei dat verkillende patrone na vore kom teen verskillende ruimtelike skale. Dit is problematies omdat patrone en patroonproses verwantskappe wat teen ‘n sekere skaal na vore kom nie noodwendig teen ‘n ander skaal geld nie. Dit verydel die begrip van hoe biotiese gegenereer en in stand gehou word. En lei daartoe dat misleidende bewaringsstrategieë en -beleide geïmplementeer word. Die fokus van hierdie studie was dus om die verwantskap tussen huidige patrone van amfibiese rykheid en omset, die verhouding hiervan met verskeie kontemporêre omgewingsprosesse, en hoe hierdie patrone en patroonproses verhoudings in stand gehou word oor die ruimtelike grein te ondersoek. IUCN data vir die Afrotropiese gebied is gebruik om amfibiese rykheid en omsetpatrone te ondersoek met behulp van Geografiese Inligtingstelsels (GIS) en die onlangs-geformuleerde zeta diversiteit partisioneringstegniek (ζ). Hierdie patrone is dan verbind met verskeie kontemporêre omgewingsveranderlikes of omgwingsprosesse, wat veronderstel is om amfibiese diversiteit te reguleer, oor verskeie ruimtelike skale deur gebruik te maak van gewone kleinste kwadrate (GKK) en plaaslike geografies-geweegde regressie (GGR) oor drie ruimtelile skale. Die resultate toon dat amfibiese rykheid en omsetpatrone (visueel en empiries), en die verwantskap wat dit toon tot omgewingstoestande, sensitief is vir ruimtelike grein. Ruimtelike patrone was meer opmerklik teen ‘n fyner grein, maar word meer geleideli/gladder teen ‘n growwer grein. Die statistiek van die patrone dui daarop dat die skaleringseienskappe ‘n verhoogde lineêre-, mags- en eksponensiële neiging volg met verhoogde ruimtelike grein resultate van beide die GKK en GGR modelle bevestig dat kontemporêre omgewingstoestande beduidende determinante is van amfibiese rykheid en omsetpatrone. Reënval was die sterkste determinant van amfibiese rykheid en topografiese kompleksiteit het die beste verklaring gebied vir omset. Die verwantskap tussen diversiteitskomponente en omgewingstoestande was afhanklik van skaal met omgewingstoestande wat ‘n groter gedeelte van die afwyking in die biotiese patrone teen growwer as teen fyner greine verklaar. Dit word dus aanbeveel dat Stellenbosch toekomstige studies wat diversiteit patrone en hul verwantskap met omgwewingsprosesse ondersoek so doen oor verskeie ruimtelik skale om die huidiglike begrip daarvan te verbeter. Thesis (MSc)--Stellenbosch University, 2017.

Methods for sugarcane harvest detection using polarimetric SAR

2017-05-10T13:27:49Z

Methods for sugarcane harvest detection using polarimetric SAR Portnoi, Michael ENGLISH ABSTRACT: Remote sensing has long been used as a method for crop harvest monitoring and harvest classification. Harvest monitoring is necessary for the planning of and prompting of effective agricultural practices. Traditionally sugarcane harvest monitoring and classification within the realm of remote sensing is performed with the use of optical data. However, when monitoring sugarcane, the growth period of the crop requires a complete set of multi-temporal image acquisitions throughout the year. Due to the limitations associated with optical sensors, the use of all weather, daylight independent Synthetic Aperture Radar (SAR) sensors is required. The added polarimetric information associated with fully polarimetric SAR sensors result in complex datasets which are expensive to acquire. It is therefore important to assess the benefits of using a fully polarimetric dataset for sugarcane harvest monitoring as opposed to a dual polarimetric dataset. The dual polarimetric dataset which is less complex in nature and can be acquired at a fee much less than that of the fully polarimetric dataset. This thesis undertakes the task of identifying the value of fully polarimetric data for sugarcane harvest identification and classification. Two main experiments were designed in order to complete the task. The experiments make use of fully polarimetric RADARSAT-2 C-band imagery covering the southern part of Rèunion Island. Experiment 1 made use of a multi temporal single feature differencing technique for sugarcane harvest identification. Polarimetric decompositions were extracted from the fully polarimetric data and used along with the inherent SAR features. The accuracy with which each SAR feature was able to predict the sugarcane harvest date for each field was assessed. The polarimetric decompositions were superior in classification accuracy to the inherent SAR features. The Van Zyl volume decomposition component achieved an accuracy of 88.33% whereas the inherent SAR backscatter feature (HV) achieved an accuracy of 80%. Hereby displaying the value of the added information associated with fully polarimetric SAR data. The SAR backscatter channels did not achieve accuracies as high as the polarimetric features but did display promise for single feature sugarcane harvest identification when using only a dual polarimetric dataset. Experiment 2 assessed six different machine learning classifiers, applied to single-date, dual- and fully polarized imagery, to determine appropriate combinations of machine learning classifier and SAR features. Polarimetric decompositions were extracted from the fully polarimetric data and mean texture measures were then calculated for all SAR features for both the dual- and full polatrimetric data. A multi-tiered feature reduction method was undertaken in order to reduce dataset dimensionality for the dual- and fully polarised datasets. In general, the reduction in features resulted in improved accuracies. The best sugarcane harvest accuracy was achieved using the Maximum likelihood classifier using on the HV and VV backscatter channels (96.18%). The results from Experiments 1 and 2 indicate that SAR C-band data is suitable for sugarcane harvest monitoring and mapping in a tropical region where optical data have limitations associated with cloud cover and large amounts of moisture in the atmosphere. With the availability of dual polarised Sentinel-1 SAR data, future research should be focussed on the use of a dual polarimetric sugarcane harvest monitoring tool and should be extended to focus not only on sugarcane but other crops which contribute largely to the agriculture and economic sectors.; AFRIKAANS OPSOMMING: Afstandswaarneming word lankal reeds gebruik as ‘n metode in die monitering van die oes van gewasse asook vir oes-klassifikasie. Oes-monitering is nodig vir die beplanning en stimulering van effektiewe landboupraktyke. Tradisioneel word suikerriet oes-monitering en klassifisering, binne die raamwerk van afstandswaarneming, uitgevoer met die gebruik van optiese data. Tog, met die monitering van suikerriet, vereis die groeiperiode van die gewas ‘n volledige stel multi-temporale beeldverwerwings dwarsdeur die jaar. As gevolg van die beperkings geassosieer met optiese sensors, word die gebruik van daglig onafhanklike sintetiese gaatjie radar sensors, eerder bekend as Sintetiese Apertuur Radar (SAR) sensors, vir gebruik in alle weersomstandighede, vereis. Die bykomende polarimetriese informasie geassosieer met ten volle gepolarimetriese SAR sensors lei tot komplekse datastelle wat duur is om aan te skaf. Dit is daarom belangrik om die voordele van die gebruik van ‘n ten volle gepolarimetriese datastel vir suikerriet oes-monitering in teenstelling met ‘n tweeledige polarimetriese datastel wat minder kompleks van aard is en teen ‘n fooi veel minder as dié van die ten volle gepolarimetriese datastel verkry kan word, te evalueer. Hierdie tesis onderneem die taak van die identifisering van die waarde van ten volle gepolarimetriese data vir suikerriet oes-identifikasie en -klassifikasie. Twee hoof-eksperimente is ontwerp om die taak te voltooi. Die eksperimente gebruik ten volle gepolarimetriese RADARSAT-2 C-band beelde wat die suidelike deel van Reunion-eiland dek. Met eksperiment 1 is gebruik gemaak van 'n multi-temporale enkelkenmerk differensie- tegniek vir suikerriet oes-identifisering. Polarimetriese ontledings is uit die ten volle gepolarimetriese data geneem en saam met die inherente SAR kenmerke gebruik. Die akkuraatheid waarmee elke SAR kenmerk in staat was om die suikerriet oes-datum vir elke veld te voorspel, is geëvalueer. Die polarimetriese ontledings was beter in klassifikasie- akkuraatheid as die inherente SAR kenmerke. Hiermee word die waarde van die bykomende inligting geassosieer met ten volle gepolarimetriese SAR data, geopenbaar. Die SAR teruguitsaaiingskanale het nie akkuraathede so hoog soos die polarimetriese kenmerke bereik nie, maar het belofte getoon vir enkelkenmerk suikerriet oes-identifikasie wanneer slegs van 'n tweeledige polarimetriese datastel gebruik gemaak word. Met eksperiment 2 is ses verskillende masjien-leer klassifiseerders, toegepas op enkeldatum, tweeledige en ten volle gepolariseerde beelde, geëvalueer om toepaslike kombinasies van masjien-leer klassifiseerder en SAR kenmerke te bepaal. Polarimetriese ontledings is geneem uit die ten volle gepolarimetriese data en beteken dat tekstuur afmetings toe bereken is vir alle SAR kenmerke vir beide die tweeledige- en ten volle gepolarimetriese data. 'n Multi-reeks kenmerkreduksie-metode is onderneem om datasteldimensionaliteit te verminder vir die tweeledige- en ten volle gepolariseerde datastelle. Oor die algemeen het die redusering van kenmerke verbeterde akkuraatheid tot gevolg gehad. Die beste suikerriet oes-akkuraatheid is behaal deur die Maksimum waarskynlikheid klassifiseerder met behulp van die HV en VV teruguitsaaiingskanale (96,18%) te gebruik. Die resultate van eksperimente 1 en 2 dui daarop dat SAR C-band data geskik is vir suikerriet oes- monitering en kartering in 'n tropiese streek waar optiese data beperkings toon wat geassosieer word met wolkbedekking en groot hoeveelhede vog in die atmosfeer. Met die beskikbaarheid van tweeledige gepolariseerde Sentinel-1 SAR data, behoort toekomstige navorsing gefokus te wees op die gebruik van 'n tweeledige polarimetriese suikerriet oes- moniteringshulpmiddel en behoort dit uitgebrei te word om te fokus nie net op suikerriet nie, maar ook ander gewasse wat grootliks bydra tot die landbou- en ekonomiese sektore. Thesis (MA)--Stellenbosch University, 2017.

The extent of urban densification in Stellenbosch

2017-05-16T09:42:11Z

The extent of urban densification in Stellenbosch Kruger, Ruan ENGLISH ABSTRACT: There is a perpetual burden to supply accommodation to increasing population numbers in Stellenbosch. The most ideal way in which the property market is able to cater for this demand is through the development of high-density accommodation (Donaldson & Morkel 2012). Densification is a national spatial strategy aimed at integrating cities socially and spatially (Stellenbosch Municipality 2012a). However, there is a notion that densification in Stellenbosch is implemented in an ad hoc manner due to the lack of adequate policies regulating development in the town (Donaldson & Morkel 2012). What the impact may be on urban space is not known yet. Thus, it was regarded as valuable to determine the extent of urban densification in order to minimise undesired spatial consequences for future generations. Through quantitative data, the study aimed to determine where, to what extent and why densification took place in a selected area of Stellenbosch from 2000 to 2016. The study objectives were to identify properties on which densification had taken place, to identify the most prominent methods implemented towards densification, to map the changes in residential density, to identify existing policy documents and to make recommendations for the densification and future growth of the town. The study primarily focused on changes in residential densities, e.g. where there was a single dwelling unit in the past there now are multiple dwelling units on the same plot. Commercial and industrial units were excluded from the study. Sites that were under construction were included based on the planned number of units. The study entails a literature review and the compilation of quantitative data from Stellenbosch Municipality. The extent of densification was calculated by dividing the number of dwelling units by the hectares of land (du/ha = density). Based on the findings, the study concludes that densification has been a prominent feature in all the zones under study since 2000, excluding Zones 16 and 30. Due to several factors, the zones in the study area provide an obvious choice for densification in Stellenbosch. These factors relate to proximity and need for convenience, the existing infrastructure, housing demand and supply, as well as the availability of land and subsequent development opportunities. The results indicate that, although there are areas where no consolidation occurred, the consolidation of properties remains the most prominent method of densification since 2000. This is followed by the construction of additional dwelling units and the construction of multiple attached dwelling units. The study suggests that, although spatial planning policies exist in Stellenbosch, they may not be adequate and/or sufficiently enforced. The study recommends that the Municipality should identify suitable locations for densification and identify Council-owned land that is available for the development or redevelopment of new and existing buildings. Available land should be re-zoned, where necessary, in line with specifically drafted planning strategies for a given area. Incentives should be used as a tool to encourage developers to develop land if it meets the developmental guidelines determined by the context-specific planning strategies. Guidelines should ideally incorporate the holistic principles of densification, such as socio-economic integration, mixed use, sustainable transport, appropriate densities, sense of community, environmental consciousness and functional viability.; AFRIKAANSE OPSOMMING: Stellenbosch staar ’n voortdurende uitdaging in die gesig om verblyf aan die groeiende aantal inwoners te verskaf (Donaldson & Morkel 2012). Die beste manier om hierdie vraag na verblyf aan te spreek is deur die oprig van hoëdigtheid verblyf. Verdigting is ’n nasionale ruimtelike strategie wat beoog om stede ruimtelik en sosiaal te integreer (Stellenbosch Municipality 2012a). Daar word egter beweer dat verdigting in Stellenbosch op ’n ad hoc manier geïmplementeer word as gevolg van ’n tekort aan toepaslike riglyne om ontwikkeling in die dorp te reguleer (Donaldson & Morkel 2012). Wat die impak op die stedelike ruimte sal wees, is tans onbekend. Dit is dus waardevol om die mate van stedelike verdigting te bepaal om ongewensde ruimtelike gevolge vir die nageslag te minimaliseer. Deur kwantitatiewe data beoog die studie om te ontleed waar, tot watter mate en hoekom verdigting plaasgevind het in die area wat afgebaken word deur Merrimanlaan, die R44, die R310 en Simonsbergweg vanaf die jaar 2000 tot 2016. Die doel van die studie was om erwe te identifiseer waar verdigting plaasgevind het, om te identifiseer watter metodes geïmplementeer is om verdigting te bereik, om die verandering in verdigting te karteer, om bestaande beleidsdokumente met betrekking tot verdigting te identifiseer en terselfdertyd voorstelle te maak vir die verdigting en toekomstige groei van die dorp. Die studie fokus primêr op die verandering van residensiële verdigting, bv. waar daar ’n enkele woonhuis in die verlede was, is daar nou veelvuldige wooneenhede op dieselfde erf. Industriële en kommersiële eenhede word dus nie in berekening geneem nie. Die studie behels ’n literatuuroorsig, sowel as ’n samestelling van kwantitatiewe data wat deur die Munisipaliteit van Stellenbosch beskikbaar gestel is. Die mate van verdigting is bereken deur die hoeveelheid wooneenhede te deel deur die hektaar land waarop die eenhede gebou is (du/ha = verdigting). Die bevindinge van die studie bewys dat verdigting ’n prominente rol gespeel het met betrekking tot al die sones in die studiegebied sedert die jaar 2000, met die uitsondering van Sones 16 en 30. As gevolg van verskeie faktore is die sones in die studiegebied ’n logiese keuse vir verdigting in Stellenbosch. Hierdie faktore sluit in nabyheid en die behoefte aan gemak, die bestaande infrastruktuur, die vraag en aanbod van behuising, asook die beskikbaarheid van grond en gevolglike ontwikkelingsgeleenthede. Die resultate dui voorts aan dat, alhoewel konsolidasie nie in al die gebiede plaasgevind het nie, konsolidasie steeds die prominentste metode van verdigting sedert 2000 was. Die tweede prominentste metode was die konstruksie van addisionele wooneenhede, gevolg deur die konstruksie van veelvuldige gekoppelde wooneenhede. Die studie stel voor dat, alhoewel ruimtelike beplanningsbeleide vir Stellenbosch bestaan, dit nie altyd volledig is of ten volle afgedwing word nie. Die studie beveel aan dat die Munisipaliteit toepaslike grond vir verdigting identifiseer en dat enige Raadsgrond vir ontwikkeling en herontwikkeling van nuwe en bestaande geboue geïdentifiseer en beskikbaar gestel word. Waar moontlik moet beskikbare grond in lyn met die opgestelde beplanningstrategieë van toepassing op ‘n spesifieke area hersoneer word. Aansporings kan gebruik word as ’n instrument om ontwikkelaars aan te moedig om grond binne die ontwikkelingsriglyne te ontwikkel, soos voorgeskryf deur konteks-spesifieke beplanningstrategieë. Riglyne moet die holistiese beginsels van verdigting soos sosio-ekonomiese integrasie, gemengde gebruik, omgewingsbewustheid, volhoubare vervoer, toepaslike digtheid, gemeenskapsgevoel en funksionele uitvoerbaarheid in aanmerking neem. Thesis (MA)--Stellenbosch University, 2017.

The socio-economic wellbeing of small mining towns in the Northern Cape

2017-05-05T12:05:07Z

The socio-economic wellbeing of small mining towns in the Northern Cape Gardiner, Avril Edward Mathew ENGLISH ABSTRACT: With South Africa being a developing country in many respects, the management of natural resources is of high importance. It should therefore be determined how these resources are managed and what happens to the capital generated by the extraction of these resources. The resource curse hypothesis will be used as a base to understand why there are so many underdeveloped communities in places where these resources are extracted. The aim of this study was to investigate the nature and extent of the economic and social conditions of the communities of small mining towns in the Northern Cape. The research objectives of the study were (1) to study the literature on the effects of mining on mining town communities as well as the responses to these effects on human well-being and quality of life; (2) to identify key dimensions and indicators to determine social and economic well-being; (3) to show the change in socio-economic well-being as well as demographics over a ten-year period, and identify the factors determining changes; (4) to rank these towns according to their level of socio-economic well-being; and (5) to investigate the current climate of social and economic well-being in two case study towns by conducting interviews with key stakeholder. The study followed an exploratory sequential mixed-methods approach. Quantitative data was obtained using the census data of 2001 and 2011. A composite indicator index was then formulated to show the level of quality of life and human well-being of these towns. The towns were ranked according to this index and two case studies were done, one near the top and one near the bottom of the ranking. Data was captured and analysed using STATISTICA, Excel and ArcGIS. Perceptions on the current state of development and the impact of mining on these communities were obtained by semi-structured interviews with key stakeholders in the public and private sectors. The findings indicate that the resource curse does exist in small mining towns in the Northern Cape, which is a frontier region. It was also found that small towns are dependent on a single industry, in this case mining andhave few alternatives when it comes to diversification. It is also difficult for government to drive development since they, too, are dependent on the financial input of these mining companies. The findings in this study should assist policy-makers in government and the mining companies to identify the possible shortcoming of development strategies and plans, and in formulating these strategies and plans in accordance with the specific circumstances of each of these small towns Keywords and phrases: Socio-economic wellbeing, quality of life, mining towns, frontier region, resource curse, resource dependence, corporate social responsibility, composite indicator index; AFRIKAANS OPSOMMING: Suid-Afrika is ‘n ontwikkelende land in baie opsigte en daarom is die bestuur van natuurlike hulpbronne van die uiterste belang. Daar moet daarom bepaal word hoe hierdie hulpbronne bestuur word en hoe die kapitaal wat deur die ontginning van hierdie hukpbronne generereer word, aangewend word. Die “hulpbronvloek” (“resource curse”) hipotese word in hierdie studie gebruik ten einde te begryp waarom daar so baie onder-ontwikkelde gemeenskappe is in die gebiede waar hierdie hulpbronne ontgin word. Die doel van hierdie studie is om die aard en omvang van die ekonomiese en sosiale omstandighede van die gemeenskappe in klein myndorpe in die Noord- Kaap te ondersoek. Die navorsingsoogmerke van die studie is (1) om die literatuur oor die invloed van mynbedrywighede op gemeenskappe in myndorpe, en die reaksies op hierdie invloede op menslike welstand en lewensgehalte te ondersoek; (2) om die hoof-dimensies en indikatore van sosiale en elkonomiese welstand te bepaal; (3) om die verandering in sosio-ekonomiese welstand en demografie oor ‘n tydperk van tien jaar aan te toon, en om die faktore wat verandering bepaal, te identifiseer; (4) om die dorpe volgens die vlak van sosio-ekonomiese welstand op ‘n ranglys te plaas; en (5) om die huidige klimaat van sosiale en ekonomiese welstand te ondersdoek deur onderhoude met sleutel belangegroepe in twee gevallestudies te voer. ‘n Eksploratiewe sekwensiële gemengde metode benadering word in die studie gebruik. Die sensusdata van 2001 en 2011 word as die kwantitatiewe data gebruik. ‘n Saamgestelde indeks van indikatore is geformuleer om die vlak van lewensgehalte en menslike welstand in die dorpe aan te toon. Die dorpe is volgens hierdie indeks op ‘n ranglys geplaas, en twee gevallestudies is gedoen., met die een dorp naby die bokant en die ander een naby die onderkant van die lys. STATISTICA, Excel en ArcGIS is gebruik om die data vas te lê en te analiseer. Persepsies van die huidige stand van ontwikkeling en die impak van mynbedrywighede op hierdie gemeenskappe is bekom deur semi-gestruktureerde onderhoude met sleutel belangegroepe in die openbare sektor en privaatsektor te voer. Die bevindinge dui aan dat die hulpbronvloek wel in klein myndorpe in die grensgebied van die Noord-Kaap bestaan. Daar is ook bevind dat daar beperkte opsies met betrekking tot diversifikasie bestaan in die geval van klein dorpe wat vir hulle voortbestaan van een industrie, in hierdie geval die mynbedryf, afhanklik is. Dit is moeilik vir die staat om ontwikkeling aan te voer aangesien die staat vir finansiering ook van die mynmaatskappye afhanklik is. Die bevindinge in hierdie studie behoort beleidmakers in die regering en die mynmaatskappye te help om moontlike tekortkomings van ontwikkelingstrategieë en -planne te identifiseer, en om hierdie strategieë en planne ooreekomstig die spesifieke omstandighede van elkeen van hierdie klein dorpe te formuleer. Thesis (MA)--Stellenbosch University, 2017.

Spatial visualization of uncertainty

2017-05-08T14:11:38Z

Spatial visualization of uncertainty Christ, Sven ENGLISH ABSTRACT: Geospatial information has become more accessible since the early 2000s. Uncertainty has remained a constant in data, due to various factors, including scale and real world conceptualization. Geospatial products are frequently used to inform decision makers on key decisions, with little understanding of the quality of the data. However, accuracy assessments have improved significantly since the visual screening that was used in the 1950s, now providing statistics such as the Kappa coefficient, root mean square error (RMSE) and the confusion matrix. Two questions thus arise: 1) do those using the data inform themselves about the quality of data; and 2) can visualization of the uncertainty in spatial data aid in the communication of the data quality? This research was achieved in three tasks: 1) evaluate the South African perception on data quality; 2) develop an uncertainty visualization tool; 3) evaluate the uncertainty visualization tool. The first task was achieved through a quantitative survey of people working in the South African geospatial industry. Despite a limited response, the findings indicated that those working with geospatial data do not always seek to verify the quality of the data they are using. It also came to light that most of those who do not verify the quality of their data, would like to have the uncertainty in the data visualized. Task 2 aimed at developing a tool for the visualization of spatial uncertainty (Uview). Uview was based on the findings from Task 1 supplemented by recommendations from literature and other uncertainty visualization tools. The tool was developed for continuous raster datasets only and uses the z-score and modified z-score as its main statistics for visualization. Standard accuracy assessment statistics (global data quality statistics), such as RMSE and mean absolute error (MAE) have also been included in Uview to make it an accuracy assessment and uncertainty visualization tool for continuous raster data. Lastly Task 3, the evaluation of Uview was done using a two-pronged approach. The first part encompassed investigating the usability of the tool. In this phase the visualizations were used to derive relationships between digital elevation models (DEM), uncertainty and a watershed product. It was found that Uview does provide useful information, and watersheds are sensitive to deviations from true value at key locations more than the magnitude of the deviation. When Uview was evaluated by twelve people in the geospatial industry they all agreed that though improvements can be made, as it presents itself currently it is already a useable product that can add value. All respondents agreed that the visualization improves the comprehension of the statistics, and so of uncertainty.; AFRIKAANS OPSOMMING: Ruimtelike inligting het sedert die vroeë 2000's meer toeganklik geword. Onsekerheid het 'n konstante in data gebly as gevolg van verskeie faktore, insluitend skaal en werklike wêreld konseptualisering. Ruimtelike produkte word dikwels gebruik om besluitnemers in te lig oor belangrike besluite, met min begrip van die kwaliteit van die data. Tog het akkuraatheid assessering aansienlik verbeter sedert die visuele metodes wat in die 1950's gebruik is, ook met die verskaffing van statistiek soos die Kappa-koëffisiënt, wortel-gemiddelde-kwadraat fout (RMSE) en die verwarringsmatriks. Twee vrae ontstaan dus: 1) neem die gebruikers van die data die tyd om hulself te vergewis met die kwaliteit van data; en 2) kan visualisering van die onsekerheid in ruimtelike data die kommunikasie van die data kwaliteit ondersteun? Hierdie navorsing is behaal in drie take: 1) evalueer die Suid-Afrikaanse persepsie oor data kwaliteit; 2) ontwikkel 'n onsekerheid visualisering hulpmiddel; 3) evalueer die onsekerheid visualisering hulpmiddel. Die eerste taak is behaal deur 'n kwantitatiewe opname van mense wat betrokke is in die ruimtelike inligtingsbedryf in Suid-Afrika. Ten spyte van 'n beperkte reaksie, het die bevindinge aangedui dat diegene wat met ruimtelike data omgaan nie altyd daarna streef om die data gehalte te verifieer nie. Dit het ook aan die lig gekom dat die meeste van diegene wat nie hul data gehalte verifieer nie, wel belangstel in ‘n onsekerheid visualisering van die data. Taak 2 was gemik op die ontwikkeling van 'n instrument vir die visualisering van ruimtelike onsekerheid (Uview). Uview is gebaseer op die bevindinge van Taak 1 aangevul deur aanbevelings vanuit die literatuur en ander onsekerheid visualisering hulpmiddels. Die instrument is ontwikkel vir deurlopende roosterdatastelle en maak gebruik van die z-telling en gemodifiseerde z-telling as belangrikste statistieke vir visualisering. Standaard akkuraatheid assessering statistieke (globale data kwaliteit statistieke), soos RMSE en gemiddelde absolute fout (MAE) is ook ingesluit in Uview om dit 'n akkuraatheid assessering en onsekerheidsvisualisering hulpmiddel vir deurlopende roosterdata te maak. Laastens die evaluering van Uview (Task 3) is gedoen met behulp van 'n tweeledige benadering. Die eerste deel het ondersoek ingestel na die bruikbaarheid van die instrument. In hierdie fase is die visualiserings gebruik om verhoudings tussen digitale elevasie modelle (DEM), onsekerheid en 'n waterskeiding produk af te lei. Daar is bevind dat Uview nuttige inligting verskaf, en waterskeidings is meer sensitief vir afwykings van werklike waardes op belangrike plekke meer as die grootte van die afwyking. Tydens die Uview evaluering deur twaalf mense vanuit die ruimtelike inligtingsbedryf, het almal saamgestem dat hoewel verbeteringe gemaak kan word, die produk soos dit tans daar uitsien alreeds 'n bruikbare produk is wat waarde kan toevoeg. Al die respondente het saamgestem dat die visualisering die begrip van die statistieke verbeter, en so ook van onsekerheid. Thesis (MA)--Stellenbosch University, 2017.

The nature extent and locational dynamics of Tygervalley in the Cape Town economic inequality context

2017-05-08T09:38:17Z

The nature extent and locational dynamics of Tygervalley in the Cape Town economic inequality context Damons, Monique ENGLISH ABSTRACT: Inequality is a persistent problem in post-apartheid South Africa. This study responds to the inequity in South Africa’s current pattern of spatial development and spatial trajectory, specifically the lack of spatial economic transformation in its cities. It aims to provide a deeper spatial understanding of economic inequality in Cape Town, specifically the continued lack of investment and economic growth in poor city areas compared to continued investment and growth in wealthy areas. The study provides insight into economic activity in Tygervalley, a wealthy business precinct in the northern suburbs of Cape Town, through a detailed analysis of the location of private investment and business. Businesses in Tygervalley were identified and their features and locational decisions determined and analysed. Conditions conducive to business growth in the northern suburbs, the level and types of business activity the area, as well as barriers to business growth in the south-east of Cape Town were determined based on these findings. Quantitative and qualitative data were collected from businesses in Tygervalley and analysed using multivariate and thematic approaches respectively. The study had an embedded mixed methods design with positivistic, phenomenological and pragmatic philosophical underpinnings. Findings could inform policies to address the city’s uneven growth pattern and encourage job creation in south-eastern Cape Town. The results show that wealthy areas such as Tygervalley continue to reflect the characteristics that promote economic growth while poor areas such as south-eastern Cape Town do not. Since initial assessments 15 years ago, little has changed in altering barriers to development in poor areas of the city. Policies and initiatives operating during this period have failed to create a spatially more equitable city by creating conditions conducive to business growth in poor areas. Cape Town is continuing on a general inequitable economic trajectory with economic growth proliferating and being reinforced in northern wealthy areas with comparatively little growth in poor areas such as the south-east. This trend does not support urban integration to the economic benefit of poorer areas in Cape Town. There is still a great need for improved proactive (particularly local) governance directing investment to poor areas through public-private-civil partnership mechanisms.; AFRIKAANS OPSOMMING: Ongelykheid is ’n hardnekkige probleem in Suid-Afrika ná apartheid. Hierdie studie is in reaksie tot die ongelykheid in Suid-Afrika se huidige patroon van ruimtelike ontwikkeling en ruimtelike koerse, veral die tekort aan ruimtelike transformasie in sy stede. Dit poog om ’n dieper ruimtelike begrip van ekonomiese ongelykheid in Kaapstad, spesifiek die volgehoue tekort aan investering en ekonomiese groei in armer gedeeltes van die stad in vergelyking met die volgehoue investering en ekonomiese groei in die welgestelde gebiede, te bied. Hierdie studie verskaf insig tot die ekonomiese aktiwiteit in Tygervallei, ’n gegoede sakewyk in die noordelike voorstede van Kaapstad, deur middel van ’n gedetailleerde analise van die ligging van private investering en besighede. Besighede in Tygervallei is geïdentifiseer en is hul kenmerke en liggingsbesluite vasgestel en geanaliseer. Gunstige toestande vir die uitbreiding van besighede in die noordelike voorstede, die vlak en tipe besigheidsaktiwiteite in die gebied, sowel as die hindernisse wat sakegroei in die suidoostelike gebiede van Kaapstad inperk, is volgens hierdie bevindinge vasgestel. Kwantitatiewe en kwalitatiewe data is van besighede in Tygervallei verkry en is geanaliseer deur onderskeidelik van veelvoudige en tematiese benaderings gebruik te maak. Die studie het ’n geankerde ontwerp met gemengde metodes gehad met positivistiese, fenomenologiese en pragmatiese filosofiese onderstutting. Die bevindinge (van hierdie studie) kan gebruik word om beleide te skep wat die ongelyke groeipatroon van die stad kan aanspreek en die skepping van werksgeleenthede in die suidoostelike gedeeltes van Kaapstad aanmoedig. Die resultate dui aan dat gegoede gebiede soos Tygervallei steeds die eienskappe wat ekonomiese groei bevorder, reflekteer terwyl dit nie in arm areas soos die suidoostelike gebiede van Kaapstad, voorkom nie. Sedert die aanvanklike waardebepaling 15 jaar gelede gedoen was, het daar nie veel verander om die hindernisse, wat in die weg van ontwikkeling in armer gedeeltes van die stad staan, uit die weg te ruim nie. Beleide en inisiatiewe wat in hierdie tydperk van toepassing was, het nie daarin geslaag om ’n stad te skep wat ruimtelik meer gelyk is deur gunstige toestande vir sakegroei in armer gebiede te skep nie. Kaapstad is op ’n algemene ongelyke ekonomiese koers waar in teenstelling met die min groei wat in die arm gebiede soos die suidoostelike gebiede plaasvind, ekonomiese groei in die noordelike gegoede gebiede floreer en bevorder word. Hierdie tendens ondersteun nie stedelike integrasie tot die ekonomiese voordeel van armer gebiede in Kaapstad nie, Daar bestaan steeds ’n groot behoefte vir proaktiewe staatsbestuur (veral plaaslik) om investering in arm gebiede deur middel van openbare-private-burgelike vennootskap meganismes te bestuur. Thesis (MA)--Stellenbosch University, 2017.

Assessment of coastal vegetation degradation using remote sensing in False Bay, South Africa

2017-03-15T14:17:28Z

Assessment of coastal vegetation degradation using remote sensing in False Bay, South Africa Mbolambi, Cikizwa ENGLISH ABSTRACT: The coastal zone, the interface between land and sea, faces much pressure from human activities. These coastal pressures make it difficult for the coastal zones to fulfil their natural functions, so threatening the state of coastal environments and making them vulnerable to coastal disasters and degradation. This study aimed to test whether remote sensing techniques can be implemented to assess the intactness of terrestrial coastal vegetation at the high spatial resolution required for coastal management. The study focused on the northern False Bay coast, Western Cape, South Africa. The research used is a modification of the method developed by Lück-Vogel, O’Farrell & Roberts (2013) which involved image segmentation and a habitat intactness index using image derivatives. The procedure used Worldview-2 (WV-2) images of high spatial, spectral and temporal resolution acquired on 25 February 2014 and 11 October 2014. Both images were pre-processed and segmented into meaningful objects using object-based image analysis (OBIA). Five image derivatives and the eight spectral bands were stacked into a single image to extract field-informed training points. Regression analysis was performed on eight spectral bands and five image derivatives to evaluate the most suitable bands to produce a habitat intactness index in a subsequent decision tree classification. Decision tree classification was generated using two spectral bands, namely the RED and NIR1 bands. These bands were chosen because they gave the best regression results and they are available in most sensors. The bands were also chosen because the study deals with vegetation assessment. The overall accuracy of the results was 80.5% which was a satisfactory result with a kappa value of 0.75 (75%) that indicates a substantial agreement between the remotely sensed result and the reference data. A key finding is the importance of seasonality to delineate natural and alien vegetation which is better achieved in the dry season. Validation of the results was done using the field-validation points of a field visit conducted in June 2016. The output maps generated for habitat intactness consisted of five habitat intactness classes namely highly, moderately and lightly degraded, intact vegetation and alien vegetation. The output maps can be used to inform coastal managers about conservation at a local scale. It is recommended that validation of remote sensing results be done in the same season that satellite images were taken.; AFRIKAANS OPSOMMING: Die koppelvlak tussen die land en die see, ook bekend as die kussone, verkeer onder druk weens antropologiese invloede. Menslike bedrywighede belemmer die kus se natuurlike funksie en stel die kus en sy nabygeleë omgewing bloot aan kusrampe en degradasie. Hierdie studie probeer bepaal of afstandswaarnemingstegnieke toegepas kan word om habitatsongeskondenheid langs die kus, teen ‘n geskikte resolusie vir kusbestuurdoeleindes, te modelleer. Ons fokus spesifiek op die noordelike deel van Valsbaai in die Wes-Kaap Provinsie van Suid-Afrika. Ons bou voort op metodes wat oorspronklik deur Lück-Vogel, O’Farell & Roberts (2013) gedoen is. Die voorgenoemde studie gebruik beeldsegmentasie en beeldafgeleides ten einde ‘n habitatsongeskondenheidsindeks op te stel. Die metode wat in hierdie studie gebruik word maak gebruik van twee WorldView-2 (WV-2) beelde wat teen ‘n hoë ruimtelike-, spektrale- en tydsresolusie, onderskeidelik, op 25 Februarie en 11 Oktober geneem is. Voorwerpgebasseerde beeldverwerking is toegepas om die voorverwerking en segmentasie op hierdie beelde te doen om sodoende sinvolle beeldvoorwerpe te verkry. Vyf beeldafgeleides en agt spektrale bande is gestapel om ‘n enkele beeld te vorm ten einde die toetspunte te isoleer. Regressie-analise is gedoen om die mees toepaslike bande te bepaal om ‘n habitatsongeskondenheidsindeks daar te stel deur van ‘n klassifikasie-beslissingsboom gebruik te maak. Die RED en NIR1 spektraalbande is gebruik om beslissingsboomklassifikasie te doen. Hierdie bande is gekies omdat hulle die beste regressie resultate gelewer het, beskikbaar is op die meeste sensors en omdat hierdie studie plantegroei-assesering behels. Die algehele akkuraatheid van ons bevindinge is 80.5% en word beskou as ‘n bevredigende resultaat met ‘n kappa waarde van 0.75 (75%) wat aandui dat daar ‘n wesenlike ooreenkoms tussen die afstandswaargenome resultaat en die verwysingsdata is. Een van die sleutelbevindinge is die belangrike rol wat seisonaliteit speel in die beskrywing van inheemse en uitheemse plantegroei. Sulkse beskrywings is meer wesenlik in die droë seisoen. Bevestiging van die resultate is gedoen deur van veld-validasie punte, wat tydens ‘n veldbesoek in 2016 geneem is, gebruik te maak. Die gegenereerde habitatsongeskondenheidskaarte bestaan uit vyf habitatsongeskondenheidsklasse naamlik hoog, matig- en ligtelik gedegradeer, ongeskonde plantegroei en uitheemse plantegroei. Hierdie afvoerkaarte kan gebruik word om kusbestuurders in te lig oor bewaring op 'n lokale skaal. Dit word aanbeveel dat die validasie van die afstandswaarnemingsresultate gedoen word in dieselfde seisoen waarin die satelliet beelde geneem is. Thesis (MSc)--Stellenbosch University, 2016.

Retail transformations and consumer preferences in Paarl and Stellenbosch: CBD versus decentralised mall

2017-02-24T14:19:09Z

Retail transformations and consumer preferences in Paarl and Stellenbosch: CBD versus decentralised mall Venema, Jeroen ENGLISH ABSTRACT: Shopping malls represent high shopping convenience that contains much choice, and great access and entertainment. However, from an urban geographical standpoint, shopping malls represent decentralisation, car dependency and low access by disadvantaged consumers, who live remotely, without a car, in poor neighbourhoods. Shopping malls started to compete with retain in the central business district (CBD) in several countries throughout the world, and it would seem that the CBD is losing the retail battle. Furthermore there also are social consequences, such as low access by disadvantaged consumers, and whereas this topic is discussed in the global north, there are few South African examples of CBD retail and its consumers. Therefore, the aim of this thesis was to examine the retail transformations and the consumer preferences in two medium-sized South African cities, namely Paarl and Stellenbosch, which are located in the Western Cape. Through convenience sampling on the basis of 346 surveys, in-depth interviews with key informants, retail street observations and a Google street view analysis, this research provides an overview of the retail transformations experienced in the CBD and two selected shopping malls in Paarl and Stellenbosch, in combination with the experiences and preferences of disadvantaged and advantaged consumers. The empirical findings confirmed the negative impact on retail in the CBD in Paarl after the building of a new, decentralised shopping mall along with stronger, segregated retail use. On the other hand, the empirical findings in the CBD of Stellenbosch showed a strong sign of retail resilience, alongside a decline in retail in a decentralised shopping mall. The chances of retail resilience and a more resilient CBD, such as in Stellenbosch, were explained by the literature, in the context of diverse cultural, retail and economic facilities, along with the provision of education and public areas and buildings. Furthermore, limited access to retail facilities by disadvantaged consumers in Stellenbosch was not found, probably due to the presence of a very accessible city mall for disadvantaged consumers in the Stellenbosch CBD.; AFRIKAANS OPSOMMING: Winkelsentrums verteenwoordig hoë inkopiegerief wat groot keuse, toegang en vermaak bevat. Vanuit ’n stedelik geografiese oogpunt verteenwoordig winkelsentrums egter desentralisasie, ’n afhanklikheid van voertuie en lae toegang deur benadeelde verbruikers wat op ’n afstand, en sonder ’n motor, in arm woonbuurte woon. Winkelsentrums oor die hele wêreld het begin om met waarin dit blyk dat die middestad se kleinhandel verloor die kleinhandel stryd om te kompeteer met die kleinhandel die middestad in verskeie lande. Verder is daar waarskynlik sosiale gevolge soos 'n lae toegang van benadeelde verbruikers en terwyl hierdie onderwerp word in die globale Noorde is Suid-Afrikaanse voorbeelde op kleinhandel middestad en sy verbruikers moeilik om te vind. Daarom, hierdie tesis doel is om die kleinhandel transformasies en verbruiker voorkeurs van gedesentraliseerde winkelsentrums in twee Suid-Afrikaanse mediumgrootte stede van die Paarl en Stellenbosch, geleë in die Wes-Kaap te ondersoek. Deur gerieflikheidsmonsterneming (convenience sampling) in die Paarl en Stellenbosch van n 346 opnames, in - diepte onderhoude van sleutel - informante, kleinhandel straat waarnemings en 'n Google street view -analise, hierdie navorsing bied 'n oorsig van die ervare kleinhandel transformasies van die middestad en twee gekies winkelsentrums in Paarl en Stellenbosch in kombinasie van die ervarings en voorkeurs van die benadeelde en bevoordeelde verbruikers. Die empiriese bevindinge bevestig die negatiewe impak op die kleinhandel die middestad in Paarl sedert die bou van 'n nuwe gedesentraliseerde winkelsentrum langs 'n sterker geskei kleinhandel gebruik. Aan die ander kant, die empiriese bevindinge toon 'n sterk teken van kleinhandel veerkragtigheid in die middestad van Stellenbosch langs 'n kleinhandel daling in 'n gedesentraliseerde winkelsentrum. Die kans kleinhandel veerkragtigheid en 'n meer bestand middestad soos in Stellenbosch was verklaar deur die literatuur waarin die konteks van die stad met die huidige diverse kultuur, kleinhandel, ekonomiese fasiliteite met die aanbod van onderwys en openbare areas en geboue. Verder is beperkte toegang van kleinhandel fasiliteite vir die benadeelde verbruikers in Stellenbosch nie waarskynlik gevind as gevolg van die huidige van 'n goeie toeganklike city mall vir die benadeelde verbruikers in die middestad van Stellenbosch. Thesis (MA)--Stellenbosch University, 2016.

Evaluation of SfM against tradional stereophotogrammetry and LiDAR techniques for DSM creation in various land cover areas

2017-02-24T10:40:14Z

Evaluation of SfM against tradional stereophotogrammetry and LiDAR techniques for DSM creation in various land cover areas Wenger, Sebastian Michael Benedict AFRIKAANS OPSOMMING:Struktuur-deur-Beweging (SdB) is moontlik ŉ effektiewe hulpmiddel om digitale oppervlak modelle (DOMs) en orto-mosaïek beelde te skep. Die toename in kamera-resolusie asook die ontwikkeling van bekostigbare en kommersiële onbemande vliegtuie (OVs) tegnologie het 'n basis geskep vir die effektiewe gebruik van SdB om ŉ DOM te skep. Onlangse studies wat verband hou met SdB het ŉ vertikale akkuraatheid van minder as ŉ meter in spesifieke studieomgewings voorspel. Daar is ŉ behoefte aan oppervlak modelle wat vir topologiese- en ingenieursopnames gebruik kan word, maar toegang tot hoë resolusie digitale oppervlak modelle (DOMs) is beperk vir gebiede van Suid-Afrika en slegs lae resolusie DOMs is beskikbaar vir die res van die land. SdB kan potensieel die gaping oorbrug indien konsekwente akkuraathede verkry kan word. Om die effektiwiteit van SdB vir Geografiese Inligting Stelsels (GIS) beter te verstaan het hierdie studie die ruimtelike akkuraathede van SdB met gevestigde, tegnieke (tradisionele stereofotogrammetrie en Ligopsporing en afstandskatting of LiDAR) vir DOM-skepping in wisselende grondgebruik- en grondbedekkingsomgewings. Hierdie assessering is aangepak deur elke tegniek met onafhanklike globale posisioneringstelsel (GPS) verwysingspunte, asook met mekaar te vergelyk. Daar is bevind dal LiDAR die beste metode vir oppervlak herkonstruksie is en die meeste detail vasgevang het asook algeheel die laagste relatiewe fouttelling oor verskillende landgebruike gehad (wortel gemiddelde kwadratiese fout, WGKF, 0.57m). SdB het ŉ algehele WGKF van 0.67m behaal, terwyl stereo-fotogrammetrie die swakste WGKF van 1.22m gelewer het. SdB het beperkte vermoë getoon om in begroeide omgewings oppervlaktes te herkonstruktureer en slegs 58.2% is binne 1m van die LiDAR oppervlak. SdB het egter rye in wingerde geïdentifiseer en ŉ lae gemiddelde fout getoon toe dit met ‘n LiDAR verwysingsoppervlak vergelyk is. Stereofotogrammetrie nie die wingerdrye geïdentifiseer nie, het begroeide gebiede te veel veralgemeen en 'n laer vlak van insluiting getoon. SdB het beter resultate gelewer in beboude gebiede met 73.4- 81.4% wat binne 1 m van die LiDAR oppervlak val en het ŉ WGKF van 028-0.62m van GPS verwysingspunte af gekry. Die inter-DOM ooreenkoms van SdB in beboude omgewings wys daarop dat SdB moontlik beter kan wees vir data smelting as stereo-fotogrammetrie. Die herkonstruksie van beboude gebiede was voldoende, maar is deur baie dig beboude gebiede wat verdere ongewenste veralgemening van oppervlakmodelle veroorsaak. LiDAR is steeds die beste tegniek vir DOM-skepping, maar beperkings ontstaan as gevolg van die beskikbaarheid, koste, gespesialiseerde toerusting en kundigheid wat benodig word vir die implementering van hierdie tegniek. Vir beeld-gebaseerde tegnieke lewer SDB beter resultate as stereo-fototogrammetie maar dit beteken nie noodwendig dat stereo-fotogrammetie ŉ oorbodige of verouderde tegniek is nie. SdB moet eerder beskou word as die natuurlike vertakking van fotogrammetrie wat in kleiner, hoogs gedetailleerde omgewings wat moontlik hoë temporale veranderlikheid toon gebruik kan word; ENGLISH ABSTRACT: Structure from Motion (SfM) is potentially an effective tool for the creation of digital surface models (DSMs) and ortho-mosaiced imagery. The increase in camera resolution and the emergence of affordable and commercial unmanned aerial vehicle (UAV) technology has provided a basis from which SfM can be deployed effectively for DSM creation. Recent studies with SfM have predicted a vertical accuracy of less than a meter in specific study environments. A need exists for surface models for topographical and engineering surveying but there is limited access to high resolution digital elevation models (DEMs) for parts of South Africa only and low resolution DEMs for the remainder. Potentially SfM could help to bridge this gap, if consistent accuracy can be proven. To better understand the effectiveness of SfM for Geographic Information Systems (GIS) application, this study compared spatial accuracies of SfM to well understood commercial techniques (traditional stereophotogrammetry and Light Detection and Ranging or LiDAR) in DSM creation in varying land use and land cover environments. This assessment was made by comparing each technique to an independent Global Positioning System (GPS) reference as well as relative to each other. It was found that LiDAR was the best method for surface reconstruction picking up the highest level of detail and overall the lowest margin of error over different land uses (Root Mean Square Error, RMSE, 0.57m). SfM in the same assessment found an overall RMSE of 0.67m with stereophotogrammetry performing least well with and RMSE of 1.22m. SfM showed limited reconstruction ability in vegetated environments with only 58.2% included within 1m from the LiDAR surface. SfM did, however, pick up formal crop rows and demonstrated a low mean error from a LiDAR surface reference in the vineyard land cover class. Stereophotogrammetry failed to pick up vine rows and displayed higher levels of overgeneralization in vegetated areas with a lower level of inclusion. SfM performed better in built environments with 73.4-81.4% inclusion within 1m from the LiDAR surface and a RMSE range of 028-0.62m from a GPS reference. The interDSM agreement of SFM in built environments suggested better propensity for data fusion than stereophotogrammetry. The ability to reconstruct built features was adequate but limited by highly clustered buildings resulting in overgeneralized surfaces. LiDAR is still the best technique for DSM construction but experiences limitations related to availability, cost, specialist equipment and knowledge. For image-based techniques, SfM out performed stereophotogrammetry but this does not necessarily imply stereophotoggrammetry is redundant as a technique. Instead SfM should be considered the natural extension of photogrammetry for use in smaller, highly detailed and potentially highly temporal environments Thesis (MSc)--Stellenbosch University, 2016.

Detecting informal settlements from high resolution imagery using an object-based image approach

2017-02-23T13:22:48Z

Detecting informal settlements from high resolution imagery using an object-based image approach Ballim, Khaleed ENGLISH ABSTRACT: The aim of this study was twofold: evaluate different approaches to deriving normalised digital surface models (nDSM), and develop a robust and transferable methodology for mapping informal dwellings. In the first component, three approaches to extract nDSMs were investigated: (i) light detection and ranging (LiDAR) data, (ii) high resolution aerial photographs in a process of image matching, and (iii) a series of aerial images captured using a hand-held camera using structure from motion (SfM) techniques. SfM is a relatively new technique that has not been widely used for nDSM extraction. This study represented a first attempt at evaluating the three approaches, particularly for mapping informal dwellings. The accuracy of the respective nDSMs was evaluated using vertical profiles, area-based, as well as positional-based accuracy assessment metrics. This provided a clear indication of the robustness of each of the models. Results showed that an nDSM can be successfully extracted in an informal settlement for informal dwelling mapping. Overall LiDAR achieved the highest accuracy in all three accuracy assessments, showing its ability to handle the undefined and complex morphology of informal settlements. To further test the robustness of the nDSMs, each model was applied to an independent test site with varying dwelling density and achieved improved accuracies. In the second component, the utility of high resolution WorldView-2 imagery and object-based image analysis (OBIA) techniques to develop a robust and transferable methodology for mapping individual informal dwellings in the City of Cape Town was tested. A systematic approach was used to objectively identify segmentation and classification parameters. The supervised segmentation parameter tuner (SPT) tool was used to derive optimal segmentation parameters, and was evaluated using an area-based accuracy assessment which resulted in high compactness (> 86%) and correctness (>88%). To reduce data dimensionality and optimize the classification process, the RF algorithm reduced the original WV-2 feature set (n=40) and aerial imagery (n=60) feature sets by 23% and 53%, whereas the CART algorithm reduced the same feature set by 95% and 91% respectively. For classification, a supervised approach was adopted using the random forest (RF) algorithm, and a rule-based classification using a rule set in eCognition software. Although different feature subsets were selected by the RF and CART algorithm for the WV-2 and aerial imagery, similar classification accuracies were achieved in all the test sites.; AFRIKAANS OPSOMMING: Die doel van hierdie studie was tweeledig: om die verskillende benaderings tot die skepping van genormaliseerde digitale oppervlak modelle (nDOM) te evalueer en om ŉ robuuste en oordraagbare metodologie te ontwikkel om informele nedersettings te karteer. In die eerste komponent is drie benaderings tot die onttrekking van ŉ nDOM ondersoek: (i) “light detection and ranging” (LiDAR) data, (ii) hoë resolusie lugfoto’s deur gebruik te maak van ŉ beeldbypassingsproses en (iii) ŉ reeks lugfoto’s met ŉ handgreep kamera geneem van “structure from motion” (SfM) tegnieke gebruik te maak. “Structure from motion” is ‘n nuwe tegniek wat nog nie oor die algemeen gebruik word om nDOM te verkry nie. Hierdie studie is ŉ eerste poging om die drie benaderings te evalueer, met die spesifieke doel om informele nedersettings te karteer. Die akkuraatheid van die onderskeie nDOM is geëvalueer van vertikale profiele, area-gebaseerde sowel as posisioneel-gebaseerde akkuraatheidsassessering statistieke. Dit het die robuustheid van elk van die drie modelle duidelik uitgewys. Die resultate dat ŉ nDOM van ŉ informele nedersetting met sukses verkry kan word en kan sodoende hierdie gebiede karteer. LiDAR het algeheel die hoogste akkuraatheid behaal tydens al drie akkuraatheidsevaluasies, wat hierdie metode se vermoë om die ongedefinieerde en komplekse morfologie van informele nedersettings te hanteer uit wys. Elke model is op ŉ onafhanklike toetsgebied met wisselende woningsdigthede toegepas om die robuustheid van elke nDOM verder uit te lig. In die tweede komponent van die studie word die bruikbaarheid van hoë-resolusie WorldView-2 beelde en objek-gebaseerde beeld analise (OBIA) tegnieke om ŉ robuuste en oordraagbare metodologie om individuele informele nedersettings in Stad Kaapstad te karteer getoets. ŉ Sistematiese benadering is gebruik om segmentasie en klassifikasie parameters te identifiseer. Die gerigte “segmentation parameter tuner” (SPT) is gebruik om optimalesegmentasie parameters te verkry en die akkuraatheid van die segmentasie is geëvalueer deur gebruik te maak van ŉ area-gebaseerde akkuuraatheidsassessering wat gelei het to hoë kompaktheid (> 86%) en korrektheid (>88%). Om data dimensionaliteit te verminder en die klassifikasie proses te optimeer, is die RF algoritme gebruik om die oorspronklike WorldView-2 voorwerp kenmerkstelle (n=140) en oorspronklike aerial voorwerp kenmerkstelle (n=60) ekwivalent aan ŉ dimensionaliteitsvermindering van onderskeidelik 23% en 53%, terywl die CART algoritme ‘n dimensionaliteitsvermindering van onderskeidelik 95% end 91%. ŉ Gerigte benadering tot klassifikasie is gevolg deur gebruik te maak van die “random forest” (RF) algoritme, asook ŉ reël-gebaseerde klassifikasie in eCognition sagteware. Om die robuustheid en oordraagbaarheid van die modelle te assesseer, is elke model op twee onafhanklike gebiede getoets. Thesis (MA)--Stellenbosch University, 2016

Automating land cover classification using time series NDVI: A case study in the Berg River Catchment Area

2017-02-21T09:55:04Z

Automating land cover classification using time series NDVI: A case study in the Berg River Catchment Area Adesuyi, Ayodeji Steve ENGLISH ABSTRACT: The processing of large volumes of geographic information system (GIS) and remote sensing (RS) data necessitates the development of automated techniques which are cost-effective, faster and user-friendly in order to aid spatial decision making. In this study, an automated technique for identifying agricultural land cover was developed using a custom tool. Multiple ensemble classifiers in ArcGIS workflow automation tool (MEAWAT) was tested on time-series MODIS normalised difference vegetation (NDVI) data using the Berg River catchment area of Western Cape, South Africa as a case study. Although the tool was developed to perform agricultural land cover classification using MODIS input data, the tool was subsequently applied to Landsat NDVI data of the same study extent. A few modifications to the tool were implemented to accommodate the different satellite imagery. The tool was built on an ArcGIS/Python platform, and various GIS & RS functions usually performed in a variety of different software packages were integrated, including study area selection, reprojection, classification and accuracy assessment. The NDVI phenology curve was used to create training data for the classification. Different parameters were tested which allow users to engage with different rules and derive a suitable land cover map for their purpose. MEAWAT uses decision tree and ensemble classifiers such as random forest and extra-tree as well as boosting using a meta-estimator (AdaBoost). Classification accuracies of 70.5%, 75.5%, 76.3% and 78.7% were achieved respectively with MODIS data, while an accuracy of 89% was achieved using the boosted random forest classifier on the Landsat data. It was observed that a better classification output can be derived using MEAWAT on higher resolution satellite imagery provided good training data are available. These findings highlight the potential of MEAWAT for large dataset land cover classification using different satellite imagery. In addition, it exposed limitations of the tool, indicating that various adjustments will be needed on the tool when working with other satellite imagery different from MODIS and Landsat.; AFRIKAANS OPSOMMING: Die verwerking van groot volumes geografiese inligtingstelsel- (GIS) en afstandswaarnemingsdata noodsaak die ontwikkeling van outomatiese tegnieke wat koste-doeltreffend, vinnig en gebruikersvriendelik is ten einde ruimtelike besluitneming te ondersteun. In hierdie studie is ŉ geoutomatiseerde tegniek vir die identifisering van landbou-verwante landbedekking met behulp van ŉ pasgemaakte instrument ontwikkel. Veelvuldige geheelklassifiseerder in ArcGIS outomatiese instrument (MEAWAT) is op die MODIS genormaliseerde verskil plantegroei-indeks (GVPI) tydreeksgegewens van die Bergrivieropvangsarea in die Wes-Kaap, Suid-Afrika, getoets. Alhoewel die instrument ontwikkel is om landbou-verwante landbedekking met behulp van MODIS-data te klassifiseer, is die instrument ook op Landsat GVPI-data vir dieselfde studiegebied toegepas. Die instrument is effens aangepas sodat verskillende satellietbeeldtipes geakkommodeer kon word. Die instrument is op die ArcGIS/Python-platform gebou en die GIS- en afstandswaarnemingfunksies wat gewoonlik deur ŉ verskeidenheid sagtewarepakkette vervul word, is geïntegreer, insluitende die seleksie van die studie-area, herskatting, klassifikasie en assessering van akkuraatheid. Die GVPI-fenologiekurwe is gebruik om opleidingsdata vir die klassifikasie te skep. Verskillende parameters, watgebruikers in staat stel om verskeie reëls te gebruik om ŉ geskikte grondbedekkingkaart vir hulle doeleindes te ontwikkel, is getoets. Die MEAWAT-instrument gebruik beslissingsbome en geheelklassifiseerders soos ewekansige-woud en ekstra boom, asook versterking deur middel van ŉ meta-beramer (AdaBoost). Klassifikasie-akkuraatheid van onderskeidelik 70.5%, 75.5%, 76.3% en 78.7% is met die MODIS-data verkry, terwyl 89% akkuraatheid van die Landsat-data met behulp van die versterkte ewekansige-woudklassifiseerder verkry is. Dit is waargeneem dat ŉ beter klassifikasie afgelei kan word deur MEAWAT op hoër resolusie satellietbeelde toe te pas, maar slegs indien goeie opleidingsdata beskikbaar is. Hierdie bevindinge beklemtoon die potensiaal van MEAWAT vir die klassifikasie van groot landbedekkingdatastelle deur van verskillende satellietbeelde gebruik te maak. Dit het ook beperkings van die instrument aan die lig gebring, wat aandui dat verskeie aanpassings nodig sal wees wanneer satellietbeelde wat van MODIS en Landsat verskil gebruik word. Thesis (MA)--Stellenbosch University, 2016.

The V&A Waterfront as workplace and leisure space for Capetonians

2016-06-09T07:06:46Z

The V&A Waterfront as workplace and leisure space for Capetonians De Villiers, Rozitta Elizabeth Tercia ENGLISH ABSTRACT: According to a report compiled in 2012 by Projects for Public Spaces (PPS) on behalf of UN-Habitat, one third of the world's population resided in cities in the 1950s. This figure increased to 50% in the following half century and is predicted to be two thirds by 2050. The building of new skyscrapers and rapid urban development often causes urban communities' public spaces to disappear leading to more stressful living environments in crowded urban neighbourhoods. Such stressed communities often look for alternatives to fulfil their needs to interact in nature and in open spaces. One solution to this global challenge is the popular rise of urban waterfront developments that provide a link between water spaces and cities, creating multi-use destinations, which provide urban citizens with the public spaces they need to encourage public interaction and social cohesion. The Victoria and Alfred Waterfront (V&AW) in Cape Town, now 25 years old, consists of a variety of options for visiting retail, food and beverage, leisure, commercial and public spaces. Being the most visited destinations in South Africa in 2014 (according to South African Tourism), 60% of visitors to the property are Capetonians. Some 19 269 people are employed at the V&AW and it creates about 36 162 jobs in the Western Cape. The dilemma the V&AW faces is however that the major developments and investments that have regenerated the old commercial port area into an upmarket, mixed-use complex is perceived by many locals to be a playground for high-income earners and wealthy tourists where locals feel out of place. The variety of public spaces in the V&AW are seen by many Capetonians to be dysfunctional, and places they have no reason to visit. This research aimed to investigate and understand the role of the V&AW as a workplace and leisure space for Capetonians. A qualitative and quantitative questionnaire survey was conducted to determine the perceptions of local visitors and employees about the above issues and to identify ways to encourage them to take psychological ownership (attachment) of the property. The results highlighted four areas of concern. i) the non-affordability of activities, retail options, restaurants and parking; ii) the lack of parent-child activities, which include indoor options and options for various age groups, as well as child-friendly restaurant options; iii) the need to improve the public spaces by adding more greenery, benches and free Wi-Fi; and iv) adding more functional services and offerings for employees, for example ready-cooked meal options, exercise options and specialist retailers, like a hardware shop. The study makes recommendations for making the public spaces in the V&AW more functional and accessible; as well as the introduction of some retail, entertainment and service-related offerings to address the affordability issue; and encouraging more Capetonians to frequent the V&AW through these improvements. With urbanisation taking place at an unprecedented rate and waterfronts being catalysts for urban regeneration and job creation, the pressure are increasing for urban waterfront developments, like the V&AW, to create a destination for local visitors and employees that is functional to the community it serves and to create a link between the ocean and the city where locals feels welcome, have a sense of ownership and which ultimately leads to social cohesion while creating long-term public private partnership opportunities beneficial to the socio-economic upliftment in the community in which it is located.; AFRIKAANSE OPSOMMING: Volgens 'n verslag van Projects for Public Spaces (PPS) saamgestel in 2012 vir UN-Habitat, was 'n derde van die wêreld se bevolking in die1950's reeds verstedelik. Gedurende die volgende 50 jaar het die getal vermeerder na tot die helfte en word daar voorspel dat dit twee derdes sal wees teen 2050. Die bou van nuwe toringblokke en vinnige stedelike ontwikkeling lei dikwels tot die verdwyning van gemeenskappe se stedelike openbare ruimtes wat weer lei tot stresvolle woonomgewings en oorbevolkte stedelike woongebiede. Sulke gespanne gemeenskappe soek dikwels na alternatiewe geleenthede om in aanraking te kom met die natuur en met mekaar in oop ruimtes. 'n Moontlike oplossing vir hierdie wêreldwye uitdaging is die toenemende gewildheid van stedelike waterfrontontwikkelings, wat as skakel tussen wateroppervlakke en stede dien. So word veeldoelige bestemmings geskep, wat stedelike inwoners van openbare ruimtes voorsien wat hulle nodig het om openbare interaksie en sosiale samehorigheid te bevorder. Die Victoria and Alfred Waterfront (V&AW) in Kaapstad bestaan reeds 25 jaar en beskik oor 'n verskeidenheid kleinhandel-, voedsel en drank, onstpannings, kommersiȅle en openbare ruimtes. As die bestemming wat in 2014 die meeste besoekers in Suid-Afrika gelok het (volgens Suid-Afrikaanse Toerisme), is 60% van alle besoekers aan die V&AW plaaslike inwoners. Daar is tans meer as 19 269 mense in die V&AW werksaam en dit skep ongeveer 36 162 werksgeleenthede in die Wes-Kaap. Die V&AW se dilemma is egter dat die ontwikkelings en beleggings daartoe gelei het dat die ou kommersiële hawe herontwikkel is tot 'n luukse, veeldoelige ontwikkeling wat beskou word as 'n speelplek vir die plaaslike rykes en welvarende toeriste waar die gewone Kapenaar vreemd voel. Die eiendom beskik tans oor 'n verskeidenheid openbare gebiede wat plaaslike inwoners nie almal funksioneel vind nie en daarom selfs voel dat daar geen rede is om daardie plekke te besoek nie. Die doel van die navorsing is om ondersoek in te stel en te verstaan wat die rol van die V&AW as werk- en speelplek vir Kapenaars is. 'n Kwalitatiewe en kwantitatiewe vraelysopname is onderneem om vas te stel wat Kapenaars se persepsie is rakende die bogenoemde kwessies en om maniere te vind hoe om hulle aan te moedig om emosionele eienaarskap (gehegtheid) van die V&AW te neem. Die resultate van die navorsing het vier sake beklemtoon: i) die nie-bekostigbaarheid van aktiwiteite, kleinhandelopsies, restaurante en parkering; ii) die gebrek aan ouer-kindaktiwiteite (wat binnenshuise opsies insluit vir verkillende ouderdomsgroepe) asook kindervriendelike restaurante; iii) die behoefte om die huidige openbare ruimtes te verbeter deur meer groenigheid, sit bankies en gratis Wi-Fi by te voeg; en iv) meer funksionele dienste en aanbiedinge vir werknemers, bv. klaargekookte etes, fiksheidsopsies, gespesialiseerde kleinhandel ondernemings, byvoorbeeld 'n ysterwarewinkel. Aanbevelings sluit voorstelle in oor hoe om die openbare ruimtes meer funksioneel en toeganklik te maak; die instel van sommige kleinhandel, vermaak en diensverwante aanbiedings om die kwessie van bekostigbaarheid aan te spreek; en Kapenaars deur hierdie verbeteringe aan te moedig om meer gereeld die V&AW te besoek. Met verstedeliking wat teen 'n ongekende koers plaasvind en waterfrontontwikkelings wat bekendheid verwerf as 'n katalisator vir stededlike regenerasie en werkskepping, is daar toenemende druk op stedelike waterfrontontwikkelings, soos die V&AW, om 'n bestemming vir plaaslike besoekers en die werknemers te skep wat funksioneel is vir die gemeenskap wat dit dien, en om 'n skakel tussen die stad en die see te skep waar plaaslike inwoners welkom voel, 'n gevoel van eienaarskap ervaar wat weer tot samehorigheid lei in die gemeenskap, met geleenthede vir openbare en private vennootskappe wat voordelig vir die langtermyn sosio-ekonomiese opheffing van plaaslike inwoners is. Thesis (MA)--Stellenbosch University, 2016.

Flood mapping in the Zambezi Region using Synthetic Aperture Radar

2016-05-12T07:23:55Z

Flood mapping in the Zambezi Region using Synthetic Aperture Radar Bessinger, Mariel ENGLISH ABSTRACT: Floods occur annually in the Zambezi Region during the rainy seasons, causing economic losses and social disruption. Projected changes in climate and land use could worsen the effects of floods. SAR sensors are active sensors and operate in the microwave region and are therefore not restricted by time of day or inclement weather, making them well-suited for flood monitoring. The aim of this research is to examine the use of ASAR and PALSAR images (with acquisition dates ranging from 17 March 2009 to 30 May 2009) to determine flood extent by classifying open water bodies in the Zambezi Region using two different approaches: binary thresholding and active contour models (ACMs) using the Canny edge detector as initial contour. Classified images were then statistically and visually compared to Landsat images. For ASAR images, overall accuracies ranged between 70% and 99% for the threshold classification method and 58% and 98% for ACMs. For PALSAR images, overall accuracy ranged between 54% and 91% for the threshold classification method and between 60% and 96% for ACMs. Results obtained were adequate for both methods of classification, with thresholds only slightly outperforming ACMs for ASAR images, and ACMs only slightly outperforming thresholds for PALSAR images. These methods are binary classifications, which was acceptable for delineating open water bodies, but flooded vegetation areas were present and methods need to be extended to include these areas. Sensor properties such as wavelength, incidence angle and polarisation have an effect on the effectiveness of identifying flooded water bodies. Longer wavelengths are better suited for open water detection than shorter wavelengths, because of better penetration capabilities than shorter wavelengths. Shallower incidence angles are better suited for open water detection, but steeper incidence angles are better suited for flooded vegetation. HH-polarised imagery performed the best for open water body detection when open water surfaces were smooth, but cross-polarisations performed best when surface roughness was present. Therefore, HH- and HV- polarisations should provide sufficient discriminatory power required for open water and flooded vegetation regions.; AFRIKAANSE OPSOMMING: Daar is jaarlikse vloede in die Zambezi Streek gedurende die reënseisoen wat ekonomiese verliese en ontwrigting in die gemeenskap tot gevolg het. Geprojekteerde veranderinge in klimaat en grondgebruik kan die gevolge van vloede vererger. SAR sensors is aktiewe sensors in die mikrogolf spektrum en word dus nie deur die tyd van die dag of gure weer beïnvloed nie, wat dit baie geskik maak om vloede te kontroleer. Die doelwit van hierdie navorsing is om die gebruik van ASAR en PALSAR beelde, wat tussen 17 Maart 2009 tot 30 Mei 2009 opgeneem is, te ondersoek ten einde die omvang van die vloed vas te stel deur die oopwaterliggame in die Zambezi Streek deur twee benaderings te volg: binêre drumpelwaardes en aktiewe kontoer modelle (AKMs) met die Canny rand detektor as aanvanklike kontoer. Geklassifiseerde beelde is dan statisties en visueel vergelyk met Landsat beelde. Die akkuraatheid vir ASAR beelde het tussen 70% en 99% gewissel vir die drumpel klassifikasie metode en tussen 58% en 98% vir die AKM klassifikasie metode. Die akkuraatheid vir PALSAR beelde het tussen 54% en 91% gewissel vir die drumpel klassifikasie metode en tussen 60% en 96% vir die AKM klassifikasie metode. Die resultate was voldoende vir beide klassifikasie metodes, maar drumpel waardes wat ietwat beter gevaar as AKMs met ASAR beelde en AKMs het ietwat beter gevaar as drumpelwaardes met PALSAR beelde. Hierdie metodes is binêre metodes wat aanvaarbaar was om oopwaterliggame af te baken, maar daar was oorstroomde begroeide gebiede teenwoordig en metodes moet aangepas en uitgebrei word om hierdie gebiede in te sluit. Sensor eienskappe soos golflengte, invalshoek en polarisasie het ŉ invloed op die effektiwiteit van die identifisering van oorstroomde gebiede. Langer golflengtes is meer effektief om oopwaterliggame te identifiseer as kort golflengtes weens die beter deurdringing vermoëns as kort golflengtes. Groter invalshoeke is meer geskik vir oopwaterliggaam identifisering, maar kleiner invalshoeke is meer geskik vir oorstroomde plantegroei. HH-gepolariseerde beelde het die beste gevaar met die identifisering van oopwaterliggame met ŉ gladde oppervlak, maar kruis-polarisering het beter gevaar as die oppervlakte onstuimig was, en daarom sal dit aanbeveel word om beide ŉ HH-gepolariseerde en ŉ HV-gepolariseerde beeld te gebruik om oopwaterliggame te klassifiseer. Thesis (MSc)--Stellenbosch University, 2016.

Grassland rehabilitation after alien invasive tree eradication: landscape degradation and sustainability in rural Eastern Cape

2016-06-02T07:19:35Z

Grassland rehabilitation after alien invasive tree eradication: landscape degradation and sustainability in rural Eastern Cape Okoye, Perpetua Ifeoma ENGLISH ABSTRACT: Rehabilitating grassland, a threatened biome, requires a comprehensive management approach that integrates the environmental, economic and social matters in sustaining this system. In the Eastern Cape of South Africa, three Quaternary catchments (QCs) (T35B, T12A & S50E) have been severely invaded by Invasive Alien Plants (IAPs) as well as altered by agrarian intensification and human development. Working for Water (WfW) Alien Plant Clearing Programme have been clearing IAPs in these catchments for the past twelve years. The current research aimed at establishing various degradation gradients occurring in the QCs. This was done by conducting land cover classification and change analysis over time, evaluating soil quality and assessing the success of the WfW program by quantifying the net primary production (NPP) and evapotranspiration (ET) trends on the cleared areas. A novel management scheme for decision makers, driver-pressure-state-impact-response (DPSIR) framework, was therefore suggested for managing these QCs sustainably. The soil analysis showed that phosphorus (P) levels are significantly different (P<0.05) between invaded, cleared and natural sites. High nitrogen (N) and pH were associated with Acacia proliferation in acidic soils. Object based image analysis (GEOBIA) was used for the land use land cover (LULC) classification using Landsat 8 OLI & TIRS imagery. LULC change analyses were carried out on two reference bases [National land cover (NLC) 2000 & Edited NLC (ENLC) 2000]. Land cover change analysis was facilitated by using a framework introducing labels to describe land cover change. Annual MODIS ET (MOD16)/NPP (MOD17) data were used to evaluate the rehabilitation progress in T12A using WfW clearing data. A DPSIR management framework, structuring the sustainable indicators at the QCs in a logical manner, was developed for decision and policy makers for dealing with management issues related to land use, water resources and soil quality management. The present research recommends that additional soil samples need to be collected for validation of soil nutrients status. Medium resolution Landsat imagery used for the LULC mapping provided accuracies of greater than 80%, but could not differentiate between invasive and indigenous trees. Hyperspectral or higher resolution imagery should be explored for mapping and delineating IAPs. Using coarse resolution MODIS products to model ET/NPP did not provide adequate detail of the cleared patches to describe the actual status of WfW clearings and their rehabilitation progress.; AFRIKAANSE OPSOMMING: Rehabilitasie van grasvelde, ‘n bedreigde bioom, vereis 'n omvattende benadering wat die omgewing, ekonomiese en sosiale aangeleenthede in die handhawing van 'n stelsel integreer. In die Oos-Kaap provinsie van Suid Afrika is drie kwaternêre opvanggebiede (QCs) (T35B, T12A S50E) erg deur indringerplante (IAPs) asook verandering deur landbou intensifisering en menslike ontwikkeling ge-affekteer. Die Working for Water (WfW) se uitheemse plant program roei alreeds vir die afgelope twaalf jaar IAPs in hierdie opvanggebiede uit. Hierdie navorsing is daarop gemik om verskeie agteruitgangsgradiënte wat in die QCs voorkom te bepaal deur die evaluering van grondkwaliteit, uitvoer van landbedekking klassifikasie en veranderingsontleding asook. Die WfW rehabilitasie pogings van die afgelope twaalf jaar is deur kwantifisering van die Netto primêre produksie (NPP) en evapotranspirasie (ET) tendense vir die skoongemaakte gebiede beoordeel. ‘n Nuwe bestuurskema, gebaseer op die drywer-druk-stand-impak-reaksie (DPSIR) raamwerk, word ter bevordering van volhoubaarheid in die QCs vir besluitnemers aanbeveel. Die analise van grondvoedingstowwe het getoon dat fosfor (P) beduidend (P<0.05) tussen indringer, skoongemaakte en natuurlike terreine verskil. Hoë stikstof (N) en pH hou verband met Acacia teenwoordigheid in suur gronde. Objekgerigte beeldanalise (GEOBIA) is gebruik vir die grondgebruik grondbedekking (LULC) klassifikasie met behulp van Landsat 8 OLI & TIRS beelde. LULC veranderingsanalise is op twee verwysingsbasisse [National land cover (NLC) 2000 en gewysigde NLC (ENLC) 2000] uitgevoer. Grondbedekkingsveranderingsanalise is deur ‘n raamwerk gefasiliteer wat gebruik maak van etikette om verandering te beskryf. Jaarlikse MODIS ET (MOD16) / NPP (MOD17) data is gebruik om die rehabilitasie vordering met behulp van WfW skoonmaakdata in T12A te evalueer. ‘n DPSIR bestuursraamwerk, wat die strukturering van die volhoubaarheidaanwysers vir die QCs op 'n logiese manier organiseer, is ontwikkel om besluitneming in die hantering van bestuurskwessies met betrekking tot grondgebruik, waterbronne en grondkwaliteitsbestuur te ondersteun. Hierdie navorsing beveel aan dat bykomende grondmonsters versamel moet word om die grondvoedingstofstatus te bevestig. Medium resolusie Landsat beelde wat vir die LULC kartering gebruik is het akkuraathede van meer as 80% verskaf, maar kon nie tussen indringer en inheemse bome onderskei nie. Hiperspektrale of hoër resolusie beelde moet vir kartering van IAPs ondersoek word. Die gebruik van growwe resolusie MODIS produkte om ET / NPP te modelleer het nie voldoende detail vir die skoongemaakte areas verskaf om die werklike status van WfW uitroei en rehabilitasie vordering te beskryf nie. Thesis (MSc)--Stellenbosch University, 2016.

Environmental reasoning of secondary-level schoolchildren : case study of Okahandja, Namibia

2016-01-22T06:21:25Z

Environmental reasoning of secondary-level schoolchildren : case study of Okahandja, Namibia Moolman, Tiani ENGLISH ABSTRACT: Okahandja has been identified as one of the ‘dirtiest towns’ in Namibia. The town’s location makes it an important node serving as a gateway to the leisure and tourism periphery in Namibia. However, environmental problems such as littering and the burning of household waste are threatening the local cultural and nature-based tourism industry and the aesthetic beauty of the town. These forms of pollution pose various health risks to people living in the area, to those who interact with the spaces as well as for grazing animals and the natural environment. The aim of the study was to explore the environmental reasoning of secondary-level schoolchildren of Okahandja and to establish the main determinants of their environmental knowledge, attitudes and behaviour. The research objectives of the study were (1) to study the literature on and understand the concepts and models related to pro-environmental behaviour (PEB), environmental worldview, environmental concern and place attachment; (2) conduct transect walks through the communities to gain a contextual understanding; (3) question secondary-level schoolchildren at JG van der Wath Secondary School about their environmental knowledge and concern that influence their environmental reasoning; (4) investigate the influences (im)mobility (low access to transport) and place attachment to Okahandja have on the schoolchildren’s views and perceptions of the environment; (5) explore how the children view their local environment and how they want their living environment to change; and (6) examine whether children from different ethnic groups reason differently about the environment and whether these distinctions influence their interactions with their surroundings. The study followed a mixed-methods approach. A questionnaire survey among schoolchildren elicited information supplemented by observations made during transect walks, focus group discussions and participatory drawing exercises. Data was captured and analysed using STATISTICA, Excel and ArcGIS. The findings indicate that the children are aware of and relatively well-informed about the significance of a clean and protected environment. They were also well able to identify the importance of Okahandja within the Namibian landscape. Participants, especially female participants are concerned about protecting the natural environment. Greater emphasis was placed on environmental problems that are apparent and aesthetically unpleasing such as littering, than on other environmental issues such as the chopping down of trees and the burning of household waste. Participants only have a moderate sense of attachment to Okahandja so causing them to have a weak sense of responsibility and desire to behave pro-environmentally. Although community cohesion and social ties are strong within the communities, mistrust and miscommunication between residents and local authorities were identified as major stumbling blocks to PEB. Dissatisfaction with structural opportunities was displayed through a lack of concern and cooperation, leading to high levels of environmental degradation in and around Okahandja. The children seem to possess a ‘balanced’ environmental worldview as they believe that the natural environment should be protected yet used to sustain human life. The importance of positive role models such as parents and teachers was highlighted. It is recommended that environmental education (EE) and awareness should be implemented on three levels, namely parental, school and community.; AFRIKAANSE OPSOMMING:Okahandja staan bekend as een van die ‘vuilste dorpe’ in Namibië. Die ligging van die dorp maak dit ’n belangrike nodus wat dien as ’n poort na die ontspannings- en toerisme-periferie in Namibië. Maar omgewingskwessies soos rommelstrooiing en die verbranding van huishoudelike afval bedreig die plaaslike toerismebedryf en estetiese skoonheid van die dorp wat gegrondves is op sy kultuur en die natuur. Hierdie vorme van besoedeling hou gesondheidsrisiko’s in vir bewoners in die gebied, vir diegene wat beweeg in die ruimte, vir diere wat wei en die natuurlike omgewing. Die doel van die studie was om sekondêre skoolleerlinge van Okahandja se redenering oor die omgewing te ondersoek en die bepalende faktore van hul kennis van die omgewing en hul houding en gedrag teenoor die omgewing vas te stel. Die navorsingsdoelwitte van die studie was (1) om die literatuur oor pro-omgewingsgedrag (POG), die wêreldbeskouing oor die omgewing, besorgdheid oor die omgewing en verbondenheid aan ’n plek te bestudeer en die konsepte en modelle verwant daaraan te verstaan; (2) om deur die gemeenskappe te stap (of te deurkruis) om ’n kontekstuele begrip te verkry; (3) om sekondêre skoolleerlinge van JG van der Wath Sekondêre Skool te ondervra oor hul kennis en besorgtheid vir die omgewing en vas te stel hoe dit hul redenering oor die omgewing beïnvloed; (4) om die invloed wat (im)mobiliteit (beperkte toegang tot vervoer) en plekgehegtheid aan Okahandja het op die skoolleerlinge se omgewingsienings en –persepsies te ondersoek; (5) te ontdek hoe die kinders hul plaaslike omgewing sien en hoe hulle wil hê die omgewing waarin hul leef, moet verander; en (6) om vas te stel of kinders van verskillende etniese groepe verskillend redeneer oor die omgewing en of hierdie onderskeid hul interaksie met hul omgewing beïnvloed. Die studie maak van verskillende metodes gebruik. ’n Vraelys-opname het sekere inligting aan die lig gebring, dit is aangevul deur waarnemings tydens staptogte wat die studiegebied deurkruis het, fokusgroepbesprekings en deelnemende tekenoefeninge. Inligting is opgeteken en geanaliseer deur middel van STATISTICA, Excel en ArcGIS. Die bevindings toon dat die kinders bewus en relatief goed ingelig is oor die belangrikheid van ’n skoon en beskermde omgewing. Hulle was goed in staat om die belangrikheid van Okahandja binne die Namibiese landskap te identifiseer. Deelnemers, veral vroulike deelnemers, is besorg oor die beskerming van die natuurlike omgewing. Respondente het groter klem geplaas op omgewingsprobleme wat duidelik en esteties onaangenaam is soos rommelstrooiing, eerder as ander omgewingskwessies soos die afkap van bome en die verbranding van huishoudelike afval. Deelnemers het slegs ’n redelike sin van gehegtheid aan Okahandja wat veroorsaak dat hulle ’n swak sin van verantwoordelikheid en begeerte om pro-omgewing op te tree, het. Alhoewel gemeenskapsamehorigheid en sosiale bande sterk is binne die gemeenskappe, is wantroue en gebrekkige kommunikasie tussen inwoners en plaaslike owerhede geïdentifiseer as die hoofstruikelblokke van POG. Ontevredenheid met strukturele geleenthede is geopenbaar deur ’n gebrek aan besorgdheid en samewerking wat lei tot hoë vlakke van omgewingsdegradasie in en rondom Okahandja. Dit lyk of die kinders ’n ‘gebalanseerde’ wêreldbeskouing van die omgewing het, want hulle glo dat die natuurlike omgewing beskerm moet word, maar tog gebruik moet word om menselewens te onderhou. Die belangrikheid van positiewe rolmodelle soos ouers en onderwysers het uitgestaan. Daar word aanbeveel dat omgewingsopvoeding en –bewustheid op drie vlakke, naamlik ouer-, skool- en gemeenskapsvlak geïmplementeer moet word. Thesis (MA)--Stellenbosch University, 2015.

Integrated use of polarimetric Synthetic Aperture Radar (SAR) and optical image data for land cover mapping using an object-based approach

2016-01-25T06:08:51Z

Integrated use of polarimetric Synthetic Aperture Radar (SAR) and optical image data for land cover mapping using an object-based approach De Beyer, Leigh Helen ENGLISH ABSTRACT: Image classification has long been used in earth observation and is driven by the need for accurate maps to develop conceptual and predictive models of Earth system processes. Synthetic aperture radar (SAR) imagery is used ever more frequently in land cover classification due to its complementary nature with optical data. There is therefore a growing need for reliable, accurate methods for using SAR and optical data together in land use and land cover classifications. However, combining data sets inevitably increases data dimensionality and these large, complex data sets are difficult to handle. It is therefore important to assess the benefits and limitations of using multi-temporal, dual-sensor data for applications such as land cover classification. This thesis undertakes this assessment through four main experiments based on combined RADARSAT-2 and SPOT-5 imagery of the southern part of Reunion Island. In Experiment 1, the use of feature selection for dimensionality reduction was considered. The rankings of important features for both single-sensor and dual-sensor data were assessed for four dates spanning a 6-month period, which coincided with both the wet and dry season. The mean textural features produced from the optical bands were consistently ranked highly across all dates. In the two later dates (29 May and 9 August 2014), the SAR features were more prevalent, showing that SAR and optical data have complementary natures. SAR data can be used to separate classes when optical imagery is insufficient. Experiment 2 compared the accuracy of six supervised and machine learning classification algorithms to determine which performed best with this complex data set. The Random Forest classification algorithm produced the highest accuracies and was therefore used in Experiments 3 and 4. Experiment 3 assessed the benefits of using combined SAR-optical imagery over single-sensor imagery for land cover classifications on four separate dates. The fused imagery produced consistently higher overall accuracies. The 29 May 2014 fused data produced the best accuracy of 69.8%. The fused classifications had more consistent results over the four dates than the single-sensor imagery, which suffered lower accuracies, especially for imagery acquired later in the season. In Experiment 4, the use of multi-temporal, dual-sensor data for classification was evaluated. Feature selection was used to reduce the data set from 638 potential training features to 50, which produced the best accuracy of 74.1% in comparison to 71.9% using all of the features. This result validated the use of multi-temporal data over single-date data for land cover classifications. It also validated the use of feature selection to successfully inform data reduction without compromising the accuracy of the final product. Multi-temporal and dual-sensor data shows potential for mapping land cover in a tropical, mountainous region that would otherwise be challenging to map using single-sensor data. However, accuracies Stellenbosch University https://scholar.sun.ac.za iv generally remained lower than would allow for transferability and replication of the current methodology. Classification algorithm optimisation, supervised segmentation and improved training data should be considered to improve these results.; AFRIKAANSE OPSOMMING: Beeld-klassifikasie word al ‘n geruime tyd in aardwaarneming gebruik en word gedryf deur die behoefte aan akkurate kaarte om konseptuele en voorspellende modelle van aard-stelsel prosesse te ontwikkel. Sintetiese apertuur radar (SAR) beelde word ook meer dikwels in landdekking klassifikasie gebruik as gevolg van die aanvullende waarde daarvan met optiese data. Daar is dus 'n groeiende behoefte aan betroubare, akkurate metodes vir die gesamentlike gebruik van SAR en optiese data in landdekking klassifikasies. Die kombinasie van datastelle bring egter ‘n onvermydelike verhoging in data dimensionaliteit mee, en hierdie groot, komplekse datastelle is moeilik om te hanteer. Dus is dit belangrik om die voordele en beperkings van die gebruik van multi-temporale, dubbel-sensor data vir toepassings soos landdekking-klassifikasie te evalueer. Die waarde van gekombineerde (versmelte) RADARSAT-2 en SPOT-5 beelde word in hierdie tesis deur middel van vier eksperimente geevalueer. In Eksperiment 1 is die gebruik van kenmerk seleksie vir dimensionaliteit-vermindering toegepas. Die ranglys van belangrike kenmerke vir beide enkel-sensor en 'n dubbel-sensor data is beoordeel vir vier datums wat oor 'n tydperk van 6 maande strek. Die gemiddelde tekstuur kenmerke uit die optiese lae is konsekwent hoog oor alle datums geplaas. In die twee later datums (29 Mei en 9 Augustus 2014) was die SAR kenmerke meer algemeen, wat dui op die aanvullende aard van SAR en optiese data. SAR data dus gebruik kan word om klasse te onderskei wanneer optiese beelde onvoldoende daarvoor is. Eksperiment 2 het die akkuraatheid van ses gerigte en masjien-leer klassifikasie algoritmes vergelyk om te bepaal watter die beste met hierdie komplekse datastel presteer. Die random gorest klassifikasie algoritme het die hoogste akkuraatheid bereik en is dus in Eksperimente 3 en 4 gebruik. Eksperiment 3 het die voordele van gekombineerde SAR-optiese beelde oor enkel-sensor beelde vir landdekking klassifikasies op vier afsonderlike datums beoordeel. Die versmelte beelde het konsekwent hoër algehele akkuraathede as enkel-sensor beelde gelewer. Die 29 Mei 2014 data het die hoogste akkuraatheid van 69,8% bereik. Die versmelte klassifikasies het ook meer konsekwente resultate oor die vier datums gelewer en die enkel-sensor beelde het tot laer akkuraathede gelei, veral vir die later datums. In Eksperiment 4 is die gebruik van multi-temporale, dubbel-sensor data vir klassifikasie ge-evalueer. Kenmerkseleksie is gebruik om die data stel van 638 potensiële kenmerke na 50 te verminder, wat die beste akkuraatheid van 74,1% gelewer het. Hierdie resultaat bevestig die belangrikheid van multi-temporale data vir grond dekking klassifikasies. Dit bekragtig ook die gebruik van kenmerkseleksie om data vermindering suksesvol te rig sonder om die akkuraatheid van die finale produk te belemmer. Stellenbosch University https://scholar.sun.ac.za vi Multi-temporale en dubbel-sensor data toon potensiaal vir die kartering van landdekking in 'n tropiese, bergagtige streek wat andersins uitdagend sou wees om te karteer met behulp van enkel-sensor data. Oor die algemeen het akkuraathede egter te laag gebly om vir oordraagbaarheid en herhaling van die huidige metode toe te laat. Klassifikasie algoritme optimalisering, gerigte segmentering en verbeterde opleiding data moet oorweeg word om hierdie resultate te verbeter. Thesis (MA)--Stellenbosch University, 2015.

Monitoring rehabilitation success using remotely sensed vegetation indices at Navachab Gold Mine, Namibia

2016-01-26T07:08:48Z

Monitoring rehabilitation success using remotely sensed vegetation indices at Navachab Gold Mine, Namibia Bell, Maria Aletta ENGLISH ABSTRACT: Remote sensing and vegetation indices were evaluated for its usefulness to monitor the success of the rehabilitation programme of the decommissioned tailings storage facility (TSF1) of the Navachab Gold Mine, Karibib, Namibia. The study aimed to objectively illustrate the rehabilitation progression from tailings (baseline) to soil (capping) and vegetation (planted as well as natural). Baseline data sets of 2004 and 2005 were compared with imagery of 2009, 2010 and 2011. All the images were subjected to panchromatic sharpening using the subtractive resolution merge (SRM) method before georegistration. As no recent accurate topographical maps were available of the study area, the May 2010 image was used as a reference image. All other images were georegistered to this image. A number of vegetation indices (VIs) were evaluated. The results showed that the normalised difference vegetation index (NDVI) and the transformed vegetation index (TVI) provided the most promising results. Although the difference vegetation index (DVI) and enhanced vegetation index (EVI) distinguished the vegetation, rock, and soil classes, it was not as successful as the other VIs in classifying the rain water pond. TVI and NDVI were further evaluated for their efficacy in detecting changes. This was done by generating a series of change images and by qualitatively comparing them to false colour images of the same period. Both the NDVI and TVI delivered good results, but it was found that the TVI is more successful when water is present in the images. The research concludes that change analyses based on the TVI is an effective method for monitoring mine rehabilitation programmes.; AFRIKAANSE OPSOMMING: Afstandswaarneming en plantegroei-indekse is ge-evalueer vir die gebruikswaarde daarvan om sukses van die rehabilitasieprogram vir die geslote slykdam of tailings storage facility (TSF1) van die Navachab Goudmyn, Karibib, Namibië vas te stel. Die studie se doelwit was om die progressie in die rehabilitasie van slyk (basislyn) na grond (dekmateriaal) en plantegroei (aangeplant en natuurlik) te illustreer. Basislyndatastelle 2004 en 2005 is vergelyk met 2009, 2010, en 2011 beelde. Al die beelde is panchromaties verskerp deur die subtractive resolution merge (RSM) metode voor georegistrasie uit te voer. Aangesien geen onlangse, akkurate topografiese kaarte van die studiegebied beskikbaar was nie, is die beeld vir Mei 2010 as ‘n verwysingsbeeld gebruik. Al die ander beelde is op die laasgenoemde beeld gegeoregistreer. Die resultate het gewys dat die normalised difference vegetation index (NDVI) en die transformed vegetation index (TVI) die mees belowende resultate lewer. Al het die difference vegetation index (DVI) en enhanced vegetation index (EVI) goed onderskei tussen plantegroeiklasse en grond- en gesteentesklasse was dit nie so suksesvol met die klassifikasie van die reënwaterpoel nie. TVI en NDVI is verder geëvalueer vir effektiwiteit om verandering waar te neem. Dit is gedoen deur ‘n reeks van veranderingsbeelde te skep en dit dan kwalitatief met die valskleur-beelde vir dieselfde tydperk te vergelyk. Beide die NDVI en TVI het goeie resultate gelewer, maar die TVI was meer suksesvol om beelde met water te klassifiseer. Die navorsing lei tot die gevolgtrekking dat veranderingsanalises met die TVI ‘n effektiewe metode vir die monitoring van rehabilitasie programme is. Thesis (MA)--Stellenbosch University, 2015.

Impacts of sugarcane farming on coastal wetlands of the north coast of Zululand, Kwadukuza, South Africa

2015-07-01T14:11:17Z

Impacts of sugarcane farming on coastal wetlands of the north coast of Zululand, Kwadukuza, South Africa Matavire, Melisa M. ENGLISH ABSTRACT: Wetlands are key to providing important ecosystem goods and services yet they are under threat from a number of anthropogenic activities. In particular, in this study area, agriculture in the form of sugarcane farming is a threat to wetlands as sugarcane is reliant on a good water supply. The impacts of sugarcane farming emanates from the fact that sugarcane is a mono crop that requires wetland resources and uses a lot of pesticides and fertilisers. Despite the assumed contribution of sugarcane farming to wetland loss and degradation, few studies have quantitatively assessed the spatio-temporal changes in wetland extent as well as changes in water quality because of this activity. This study assesses the impacts of sugarcane farming on wetland extent and water quality in two coastal wetlands of KwaDukuza, North coast of Zululand, South Africa. Specifically this study sought to (i) assess the impacts of sugarcane farming on the spatial extent of wetlands between 1959 and 2012, (ii) determine if sugarcane farming negatively affect water quality within the wetlands and (iii) evaluate the perceptions of local farmers regarding impacts of sugarcane farming on wetlands. Results of the study indicated an increase in the extent of Zinkwazi sugarcane fields from 62.3% to 67% between 1959 and 1989 and Nonoti sugarcane fields’ extent increased from 50.5 % to 56.4% between 1959 and 2000. The last decade from the year 2000 showed gradual decrease in the area of wetland farmed by sugarcane due to the global sugar price remaining static while the cost of farming inputs increased and due to conversion of some farms to urban developments. Unfortunately, this has not lead to an increase in wetland area as the waterfront type developments, as well as a formal settlement have replace the sugarcane in the wetlands. Water was analysed for nitrogen (N), phosphorus (P) and potassium (K) and results for both Zinkwazi and Nonoti indicated an increasing trend of N and P from upstream to the middle region of the rivers and a decreasing trend of the N and P from the middle region to downstream. Sugarcane farming does not take place below the middle region and so does not provide fresh sources of these nutrients. The downstream area where the N and P decrease also coincides with the area of the river under tidal influence such that the N and P are being diluted by the incoming tidal seawater. K showed an increasing trend from upstream to downstream and its values were higher than N and P. Concentrations of N and P above the South African water quality guidelines for aquatic ecosystem were recorded in the middle region. Furthermore, farmers’ perceived wetlands to have been transformed to agricultural land and related these changes to their sugarcane farming activities. It can thus, be concluded that sugarcane farming has resulted in wetland loss as well as deterioration of water quality within the Zinkwazi and Nonoti wetlands in KwaDukuza. In that regard, there isneed to engage farmers in wetland management programs in order to reduce the negative environmental impacts associated with sugarcane farming in wetlands.; AFRIKAANSE OPSOMMING: Vleilande is die sleutel tot die verskaffing van ‘n belangrike ekosisteem dienste, maar hulle is onder ‘n bedreiging deur 'n aantal menslike aktiwiteite. In besonder in hierdie studie area, is Argriculture in die vorm van suikerriet boerdery is bedraging vir vleilande, en suikerriet is afhanklik van 'n goeie watervoorraad. Ten spyte van die veronderstelde bydraes van suikerriet boerdery, is die vleiland aan die agteruitgang, 'n Paar studies het kwantitatief die tydruimtelike veranderinge in die vleiland, sowel as veranderinge in die gehalte van water as gevolg van hierdie aktiwiteit waargeneem. Spesifiek is hierdie studie gepoog om (i) te bepaal wat die impak van suikerriet boerdery op die ruimtelike omvang van die vleiland tussen 1959 en 2012 is, (ii) bepaal of suikerriet boerdery negatief beïnvloed is deur die gehalte van water in die vleilande en (iii) die persepsies van plaaslike boere rakende die evalueering en impak van suikerriet boerdery op die vleilande. Resultate van die studie het aangedui 'n toename in die omvang van Zinkwazi suikerriet velde van 62,3% tot 67% tussen 1959 en 1989, en die Nonoti suikerriet velde toegeneem het met 50,5% tot 56,4% tussen 1959 en 2000. Die laaste dekade van die jaar 2000 het geleidelike afname in die area van die vleilande getoon, omdat suikerriet as gevolg van die globale suiker prys die koste van boerdery-insette verhoog het, en dit het gelei tot die omskakeling van 'n paar plase na stedelike ontwikkelings. Ongelukkig het dit nie gelei tot 'n toename in die vleiland gebiede nie, met die gevolg die waterfront tipe ontwikkelings, asook 'n formele nedersetting, vervang die suikerriet in die vleilande. Water is ontleed vir N, P en K en resultate vir beide Zinkwazi en Nonoti, het aangedui 'n toenemende tendens van stikstof en Fosfor. Dit gaan stroomop na die middel-streek van die riviere en 'n dalende neiging van die N en P uit die middel streek stroomaf. Suikerriet boerdery vind nie plaas onder die middel streek nie, en so is daar nie vars bronne, wat van hierdie voedingstowwe verskaf nie. Die stroomaf gebied waar die N en P ‘n afname het, val ook saam met die gebied van die rivier onder die gety , en dit beinvloed sodanig dat die N en P se water verdun word deur die inkomende gety se seewater. K het 'n toenemende neiging van stroomop en stroomaf en sy waardes is hoër as van die N en P. Konsentrasies van N en P bo die Suid-Afrikaanse water standaard riglyne is in die middel streek aangeteken. Verder, beskou boere dat die vleilande behoort te verander om die landbougrond en verwante veranderinge aan hul suikerriet boerdery en aktiwiteite. Ons kan dus aflei dat suikerriet boerdery het gelei tot die vleiland se verlies asook die verandering in die watergehalte in die Zinkwazi en die Nonoti vleilande in KwaDukuza. In dié verband is dit nodig dat die boere in die vleiland by programme betrek word ten einde die negatiewe omgewingsimpakte wat met suikerriet boerdery gepaard gaan in vleilande te verminder. Thesis (MSc)--Stellenbosch University, 2015.