Thesis (MSc)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The recognition and description of relief features from their contour patterns is recognized as the main challenge in topographic map education. Conducting field exercises can solve this problem, but can be very time consuming. Modern technology, however, provides an alternative teaching technique by creating depictions of terrain. Important issues raised by this new approach include questions such as what these depictions should look like and how it should be presented to the user. Research presented here aims to address these issues by constructing design guidelines for terrain depiction. These design guidelines were derived from previous research and case studies. The guidelines focussed on research about how people perceive different representations of terrain and how these representations should optimally be presented. The design guidelines were constructed from research done in diverse fields such as cognitive psychology, cartography and engineering. Results of this research revealed that in order to develop an effective terrain visualization tool, it is crucial to incorporate different fields of expertise. The design guidelines were implemented with ArcView GIS and its 3D Analyst extension, which has the ability to display spatial data in three dimensions. The final product is called Terrain Visualization Tool 1.1 (TVT) and was created by customizing an ArcView GIS project (TV BUILDER) and constructing a Website (TV VIEWER). TV BUILDER creates the visualization data in the form of 20 web pages per topographic area and links them to TV VIEWER that serves as a platform to view the data. The design guidelines were implemented successfully and show the advantages of using Geographical Information Systems (GIS) in related research. / AFRIKAANSE OPSOMMING: Die identifisering en beskrywing van landskapelemente vanaf hul kontoere is geidentifiseer as die primere uitdaging in topografiese kaartonderrig. Hierdie probleem kan oorkom word deur kaartleesoefeninge in die veld te onderneem, maar dit neem baie tyd in beslag. Modeme tegnologie maak ‘n alternatiewe onderrigmedium moontlik deur die skep van verskillende landskapsuitbeeldings. Hierdie alternatief laat die vraag ontstaan hoe die uitbeeldings moet lyk en hoe dit aan die gebruiker aangebied moet word. Die doel van hierdie navorsing spreek hierdie vrae aan deur ontwerpriglyne vir landskap uitbeelding daar te stel. Die ontwerpriglyne is saamgestel deur bestudering van vorige navorsing en studies wat op hierdie gebied gedoen is. Die riglyne fokus veral op navorsing wat mense se reaksie op verskillende landskapuitbeeldings ondersoek. Die ontwerpriglyne is egter saamgestel deur navorsing wat gedoen is in velde soos kognitiewe sielkunde, kartografie en ingenieurswese. Hierdie navorsing het bewys dat inkorporasie van verskillende studievelde in die ontwikkeling van terrein visualiseringstoepassings essensieel is. Die riglyne is geimplementeer deur gebruik te maak van ArcView GIS en die 3D Analyst uitbreiding wat die vermoe het om data in drie dimensies uit te beeld. Die finale produk genaamd Terrain Visualization Tool 1.1 (TVT) bestaan uit twee komponente, naamlik ‘n aangepaste ArcView GIS projek (TV BUILDER) en ‘n webwerf (TV VIEWER). TV BUILDER skep die landskapsuitbeeldings van een topografiese area in die vorm van 20 web bladsye en verbind dit met TV VIEWER, wat as ‘n platform dien om die landskap uitbeeldings te beskou. Die ontwerpriglyne is suksesvol geimplementeer, wat die voordele van Geografiese Inligtingstelsels (GIS) in hierdie en soortgelyke toekomstige navorsing demonstreer.

No description available.

Digital elevation models (DEMs) and their derivatives such as slope, flow direction and flow accumulation maps, are used frequently as inputs to hydrologic and nonpoint source modeling. The depressions which are frequently present in DEMs may represent the actual topography, but are often the result of errors. Creating a depression-free surface is commonly required prior to deriving flow direction, flow accumulation, flow network, and watershed boundary maps. The objectives of this study were: 1) characterize the occurrence of depressions in 30m USGS DEMs and assess correlations to watershed topographic characteristics, and 2) compare the performance of two algorithms used to remove depressions and delineate flow networks from DEMs. Sixty-six watersheds were selected to represent a range of topographic conditions characteristic of the Piedmont and Mountain and Valley regions of Virginia. Analysis was based on USGS 30m DEMs with elevations in integer meters. With few exceptions watersheds fell on single 7.5minute USGS quadrangle sheets, ranged in size from 450 to 3000 hectares, and had average slopes ranging from 3 to 20 percent. ArcView (3.1) with the Spatial Analyst (1.1) extension was used to summarize characteristics of each watershed including slope, elevation range, elevation standard deviation, curvature, channel slope, and drainage density. TOPAZ (ver 1.2) and ArcView were each used to generate a depression-free surface, flow network and watershed area. Characteristics of the areas 'cut' and 'filled' by the algorithms were compared to topographic characteristics of the watersheds. Blue line streams were digitized from scanned USGS 7.5minute topographic maps (DRGs) then rasterized at 30 m for analysis of distance from the derived flow networks. The removal of depressions resulted in changes in elevation values in 0 - 11% of the cells in the watersheds. The percentage of area changed was higher in flatter watersheds. Changed elevation cells resulted in changes in two to three times as many cells in derivative flow direction, flow accumulation and slope grids. Mean fill depth by watershed ranged from 0 to 10 m, with maximum fill depths up to 40 m. In comparison with ArcView, TOPAZ, on average affected 30% fewer cells with less change in elevation. The significance of the difference between ArcView and TOPAZ decreased as watershed slope increased. A spatial assessment of the modified elevation and slope cells showed that depressions in the DEMs occur predominantly on or along the flow network. Flow networks derived by ArcView and TOPAZ were not significantly different from blue line streams digitized from the USGS quadrangles as indicated by a paired t test. Watershed area delineated by ArcView and TOPAZ was different for almost all watersheds, but was generally within 1%. Conclusions from this study are: 1) The depressions in 30 m DEMs can make up a significant portion of the area especially for flatter watersheds; 2) The TOPAZ algorithm performed better than ArcView in minimizing the area modified in the process of creating a depressionless surface, particularly in flatter topography; 3) Areas affected by removing depressions are predominantly adjacent to the stream network; 4) For every elevation cell changed, slopes are changed for two to three cells, on average; and 5) ArcView and TOPAZ derived flow networks closely matched the blue line streams. / Master of Science

Thesis (MSc)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Multi-criteria decision-making (MCDM) is a set of techniques designed specifically for the analysis of complex problems. Geographical Information Systems (GIS) focus on spatial problem-solving and spatial analysis. The integration of these methodologies offers a powerful approach to decision making. Despite the fact that most spatial decision problems are multi-criteria problems by nature, the process of MCDM is not well established or effectively integrated into the field of spatial analysis and GIS. This research focuses on bridging the gap between MCDM and GIS. To this end, a generic MCDM extension was designed and implemented in ArcView. As a result, a first version MCDM extension is offered. The extension expands ArcView's functionality with a limited set of MCDM methods. This functionality is illustrated on two problems involved with developing the tourism potential at Coutada 16 Wildlife Reserve in Mozambique. The MCDM extension facilitates procedures that allow the evaluation of spatial problems and includes the ability to deal with both raster and vector data. This system offers a generic problemsolving environment, which can be used to evaluate geographical problems of any nature. This research identifies a number of improvements to the developed functionality and successfully illustrates the potential problem-solving capabilities associated with MCDM integrated with ArcView. / AFRIKAANSE OPSOMMING: Multi Kriteria Besluitneming (MKBN) is n versameling metodes vir die analise van komplekse probleme. Geografiese Inligtingstelsels (GIS) fokus op geografiese probleemoplossing en analise. Die integrasie van hierdie twee metodologieë bied 'n kragtige benadering tot besluitneming. Ten spyte daarvan dat die meeste geografiese probleme in wese meerveranderlik van aard is, is MKBN nie effektiefbinne die raamwerk van GIS geïntegreer nie. Hierdie studie fokus op die oorbrugging van die gaping tussen MKBN en GIS. Met hierdie doel voor oë is 'n generiese MKBN-uitbreiding vir ArcView ontwerp en geïmplementeer. Die resultaat is 'n eerste- weergawe MKBN-uitbreiding. Die uitbreiding brei ArcView se funksionaliteit uit om 'n beperkte versameling MKBN-metodes in te sluit. Die nuut ontwikkelde funksies word geïllustreer aan die hand van twee probleme wat die ontwikkeling van die toerismepotensiaal vir die Coutada 16 Wildreservaat in Mosambiek aanspreek. Die uitbreiding maak voorsiening vir 'n MKBN-evaluasie van geografiese probleme en besit die vermoë om beide vektor- en roosterdata te analiseer. Hierdie stelsel verskaf 'n generiese omgewing vir probleemoplossing wat gebruik kan word om byna enige geografiese probleem te analiseer. Die studie identifiseer verbeteringe op en uitbreidings van die ontwikkelde funksies en slaag daarin om die potensiaal van probleemoplossing wat deur die integrasie van MKBN-tegnieke met ArcView moontlik gemaak word, te illustreer.

Thesis (MA)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: The visual landscape is a resource that should be managed sustainably. Sufficient tools for the effective management of visual landscapes are still lacking. Existing visualization software (including 3D Analyst) could be utilized as an aid in visual landscape management, but as such it lacks quantification functionalities. Geographical Information Systems (GIS) could effectively be used in the quantification of visual landscapes. The composition, value and experience of visual landscapes are complex and interrelated. Visual landscapes should be divided into physical and cognitive elements for management purposes. In the quantification of visual landscapes, the physical elements are effectively handled within a GIS. Insufficient research though, hampers the quantification of the visual landscape in terms of cognitive elements. Arc View GIS, including the 3D Analyst Extension, can be extended to quantify visual landscapes. Arc View's integrated development language, Avenue, was used to develop a new technique, namely The Visual Landscape Quantifier (VLQ). The VLQ-technique is an application based on a virtual landscape where a user can select observation and target locations. These locations are used to quantify the visual landscape in a chosen direction. Results are expressed as the percentage (%) of the visible land use in the selected visual landscape. The user can choose whether the results should be displayed as a list or as a graph. Wanted and unwanted elements in the landscape could be identified, aiding the management and planning of landscapes. Keywords: Visual landscape, landscape, Visual Landscape Quantifier, visualization, Arc View GIS, Avenue, Object Oriented Programming, 3D Analyst. / AFRIKAANSE OPSOMMING: Die visuele landskap is 'n hulpbron wat volhoubaar bestuur moet word, maar ongelukkig bestaan daar mm instrumente om dit effektief te bestuur. Bestaande visualiseringsprogrammatuur (insluitend Arc View 3D Analyst) kan as hulpmiddel dien in die bestuur van visuele landskappe, maar dit ontbreek kwantifiseringsfunksionaliteite. Geografiese Inligtingstelsels (GIS) kan effektief aangewend word in die kwantifisering van visuele landskappe. Die samestelling, waarde en hoe visuele landskappe ervaar word, is kompleks en interverwant. Om visuele landskappe meetbaar te maak, moet dit in fisiese en kognitiewe elemente opgebreek word. GIS hanteer die fisiese elemente van visuele landskappe effektief en gevolglik is die kwantifisering daarvan (in GIS) wel moontlik. Onvoldoende navorsing maak die kwantifisering van visuele landskappe, in terme van kognitiewe elemente, egter moeilik. ArcView GIS, insluitend die 3D Analyst-uitbreiding, kan aangepas word om visuele landskappe te kwantifiseer. 'n Nuwe tegniek, die Visual Landscape Quantifier (VLQ), is met ArcView se geïntegreerde programmeertaal, Avenue, ontwikkel. Die VLQ-tegniek berus op 'n virtuele landskap waarbinne die gebruiker toegelaat word om waarnemers- en teikenliggings te selekteer. As toepassing word die visuele landskap in die gekose rigting in terme van die persentasie (%) van sigbare grondgebruik in die geselekteerde landskap gekwantifiseer. Die gebruiker kan kies of die resultaat as 'n lys of as 'n grafiek voorgestel moet word. Moontlike gewenste of ongewenste elemente in die visuele landskap kan gevolglik geïdentifiseer word en so die bestuurs- en beplanningstaak ondersteun. Sleutelwoorde: Visuele landskap, landskap, Visual Landscape Quantifier, visualisering, ArcView GIS, Avenue, 3D Analyst, Object Oriented Programmering.

Thesis (MA)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: Timesharing is one of the sectors of the tourism industry that has grown at a tremendous rate in the recent past. In South Africa, after adverse publicity and severe internal conflict in the early years, the timeshare industry is growing as this way of holidaying becomes more popular. Much is also expected of the tourism industry as a major contributor towards improving the socio-economic situation in this country. It is therefore essential that geographers and more specifically geographical information system specialists get involved in research on timeshare and related topics. This thesis investigates the potential use of geographical information systems (GIS) in the timeshare industry in South Africa. The main focus of the research is on the development of a timeshare information system (TIS). The TIS was developed by using the ArcView GIS programme and Avenue programming language and it incorporates the points system as the most popular timeshare type in South Africa. The main aim of the TIS is to find possible holiday resort destinations within South Africa that will satisfy the timeshare owner's holiday needs, at the touch of a button. To produce these results the user is asked a series of questions and he/she is expected to make some selections. This information is then processed to make it possible for the scripts that have been compiled to extract the correct results from the destination database. This comprehensive database has been compiled from existing sources. The final results are then shown to the user on regional maps of South Africa. These maps have been compiled beforehand for use during the programming phase, but also for the purpose of doing location and spatial analysis. In conclusion, the results have been tested by means of a case example. The results produced by the TIS have been verified as being correct. Although the TIS is not ready for the timeshare market at this stage it could, with slight adjustments, be of use and is a positive step in the right direction and is in line with modem trends in the industry. Keywords ArcView / Avenue / Exchange companies / Geographical information systems (GIS) / Graphical user interface / Points system / Resort Condominium International (RCI) / South Africa / Timeshare destination database / Timeshare industry / Timeshare owners / Timeshare resort facilities / Timeshare resorts / Timesharing / Tourism geography / AFRIKAANSE OPSOMMING: Eiendomstyddeling is een van die sektore van die toerisme-industrie wat tans wêreldwyd die meeste groei toon. In Suid-Afrika waar eiendomstyddeling aanvanklik gekniehalter is deur swak publisiteit en interne konflik, toon die bedryf besondere groei soos dié manier van vakansie hou, meer gewild raak. Baie word van die toerismebedryf verwag om 'n beduidende bydrae te maak tot die verbetering van sosio-ekonomiese toestande in die land. Juis hierom is navorsing oor tyddeling en verwante onderwerpe besonder belangrik. Geograwe en meer spesifiek geografiese inligtingstelselspesialiste kan in dié opsig belangrike rolspelers wees. Hierdie navorsingsverhandeling speur die gebruiksmoontlikhede van geografiese inligtingstelsels (GIS) in die tyddeelindustrie in Suid-Afrika na. Die hoof fokus van die navorsing val op die ontwikkeling van 'n tyddeelinligtingstelsel (TIS) met behulp van ArcView GIS programmatuur en Avenue programmeertaal. Hierdie TIS poog om die keuse van 'n geskikte vakansiebestemming in Suid-Afrika vir die tyddeeleienaar en potensiële koper te vergemaklik en inkorporeer in die proses die puntestelsel as tyddeeltipe. Die program stel aan die gebruiker 'n reeks vrae en seleksie opsies, waaruit dan 'n resultaat van oorde wat aan sy/haar vakansiebehoeftes voldoen, aan hom/haar voorgehou word. Hierdie resultate word getrek uit 'n omvattende tyddeelbestemmingsdatabasis wat uit bestaande bronne saamgestel is. Hierdie databasis word op verskeie stadiums deur die loop van die gebruiksproses deur die opgestelde programkode ondervrae. Tesame hiermee word die resultate ruimtelik en nie-ruimtelik aan die gebruiker vertoon. Hierdie ruimtelike komponent hang nou saam met die kartering van die tyddeeloorde in Suid-Afrika, 'n proses waartydens die ligging en verspreiding van hierdie oorde ook aandag kry. Ter afsluiting word die resultate aan die hand van 'n toetsvoorbeeld geverifieer. Die TIS lewer bevredigende resultate en hoewel dit nie in sy huidige formaat gereed is vir die tyddeelmark nie, is dit 'n positiewe stap en in lyn met moderne neigings in die industrie. Trefwoorde ArcView / Avenue / Blybeurtbedryf / Geografiese inligtingstelsels (GIS) / Grafiese koppelvlak / Puntestelsel / Resort Condominium International (RCI) / Suid-Afrika / Toerismegeografie / Tyddeelbelang / Tyddeelbestemmingsdatabasis / Tyddeeleienaars / Tyddeelindustrie / Tyddeeloorde / Tyddeeloordfasiliteite / Tyddeling / Uitruilondernemings

>Magister Scientiae - MSc

Advances in information technology in the past two decades have seen innovations in the field of domestic and industrial computing that led to a paradigm shift in the management and operation of urban water systems by water utility companies. The traditional public management policy that focused on ensuring a minimum quality of service regardless of the costs associated with the processes of catchment, treatment and distribution of water, in many cases even unknown, have evolved towards more efficient cost sensitive models. These new wholly or partly public funded management systems improve not only the quality of service offered to users, but also optimize resources by reducing the cost and causing the minimum environmental impact. The new challenges raised by the European Water Framework1 Directive by imposing cost recovery to improve water efficiency and environmental sustainability have led to a significant change at all levels of water management. Consequently, new priorities have been established in terms of infrastructure management that require the reduction of water losses and the improvement of the water efficiency in urban networks for human consumption. Likewise, in a broader context which includes the water--energy binomial, it is also desirable to improve the energy efficiency and carbon emissions of these systems. Today, network sectoring is the most commonly used strategy to improve management and increase network performance. It basically consists of dividing the network into several smaller hydraulic sectors, where water inlets and outlets are perfectly controlled. This simplifies the task of carrying out periodic water balances in each of the sectors, and allows water loss volume to be assessed for a given period of time. As configuring network sectors is not a trivial task, it is therefore important to have appropriate tools to perform the task efficiently and effectively. Mathematical models can play an important role as decision support tools to help water managers assess the performance of water network distribution systems. This thesis aims to address the current problems of managing urban water networks by combining new information-processing technologies with innovative network modelling techniques. It intends to facilitate the system diagnosis and extend the use of models on the decision-making process to provide better solutions to the management of urban water networks. For this purpose a software extension that works on a geographic information system (GIS) has been developed. It integrates: the hydraulic and water quality simulation program EPANET 2, innovative tools for model analysis and diagnostic, automatic tools for sectoring and computing tools to conduct water balances in the sectors using actual measurements. The work demonstrates the compatibility and complementarity of GIS and hydraulic models as technologies that can be used to support the assessment and diagnosis of water distribution networks. Considering that the majority of information linked to the network system has some geographic reference, it is not surprising that GIS has become a popular tool for dealing with such information. At the same time, the integration of mathematical modelling and simulation tools, offers the GIS a new dimension in the realm of hydraulic study of water networks. Furthermore, if this specific integration is provided with new features aimed not only to facilitate the model building, but also to assist the user in decision-making using powerful algorithms based on the application of the graph theory, the result is a powerful up-to-date analytical tool, which opens up new possibilities in the field of management and efficient operation of urban water supply systems. / Bartolín Ayala, HJ. (2013). Confección de modelos de redes de distribución de agua desde un Sig y desarrollo de herramientas de apoyo a la toma de decisiones [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/33152 / TESIS

>Magister Scientiae - MSc / The Kuils River Catchment is an urban river catchment that forms part of the larger Kuils-Eerste River system draining the eastern half of the Cape Metropolitan Authority area and Stellenbosch Municipality. Rapid urbanisation has resulted in the encroachment of residential and industrial areas into the river system through channelization and sewage disposal. This research project intends to assess the quality of surface runoff in the Kuils River catchment and determining non-point source pollutant loading rates in the catchment using GIS-based modelling. The study results show how modelled potential sources of surface runoff and NPS pollutants using desktop GIS analysis tools in a sequential process that involved different levels of software applications could explain the characteristics of the catchment. With the help of the Expected Mean Concentration (EMC) values associated with surface runoff from land use/covers, NPS pollutant loads were assessed downstream towards the Kuils River Catchment outlet using the Nonpoint Source Pollution and Erosion Comparison Tool (N-SPECT) based in ArcGIS. The outputs from this model consist of predicted annual pollutant loading (mg/mvyear) for each Kuils-Eerste River that occurs in the catchment. The results have shown clearly the spatial distribution of sources of particular pollutants in the catchment. Further or advanced processing knowhow with this model might provide far reaching insights into the problem and it is however recommended that these results produced using N-SPECT be compared to those of other hydrologic models using the same inputs.