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Spatio-temporal modelling of informal settlement growth using a hybrid GIS and CA-Markov modelDaniels, Roger Hubert 03 August 2021 (has links)
The permanency and scale of informal settlement growth across the City of Cape Town cannot be promptly understood using the existing stock of human settlement planning tools and mapping techniques because the morphological patterns of informality are characterised by the complex commingling of multiple social and economic conditions, transactions, events and norms (Lejano and Del Bianco, 2018:203). In this research study, it is argued that a key focus area for future human settlement policy development should be fixed on establishing a greater understanding of the prevailing dispositions relating to how past and future morphological processes of informal settlements evolve. Towards acquiring this understanding, the research study develops a hybrid GIS and Cellular Automata Markov model, to simulate the future spatio-temporal growth of informal settlements in the City of Cape Town, Western Cape, South Africa from 2011 to 2051. To simulate growth, a raster-based model was operationalized using a Computer Simulation Package called TerrSet. The model inputs were determined by means of an online survey with various experts, and 13 model drivers were identified. These drivers were populated utilising, census data and other locational data for 2001 and 2011, sourced from Statistics South Africa and the City of Cape Town's Corporate GIS unit. This hybrid model was calibrated, by altering the size of the input grid cells and comparing the projected outputs with the actual 2018 land use dataset. To simulate growth, the calibrated hybrid model uses: Multi-Layer Perceptron Neural Network modelling components to determine a transitional probability map; Transitional probability matrix to determine the transitional rules for vacant-to-informal land use conversion; Markov Chain component to allocate the amount of future vacant-to-informal land use changes; and Cellular Automata to enable the spatial representation of vacant-to-informal grid cell changes. This model presents a novel approach for simulating informal settlement, and weighs in on the fragmented scientific debates in the field of (dynamic) hybrid spatial process modelling. Based on the simulation results, the main findings conclude that: drivers related to the location of informal dwelling structures, no access to piped water and high unemployment have the biggest effect on model accuracy; by 2031 the morphological patterns of informal settlement growth will begin to shift affecting additional lower to middle class communities located along the Cape Flats; and between 2031 and 2051 the location of informal settlements will move from the peri-urban regions into the urban regions of the Metropolitan.
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Establishment of Accuracy Testing Facilities for Terrestrial Laser ScannersDavison, Wayne 18 February 2019 (has links)
Measurement instruments that are required for high precision and reliable work need to have regular checks to ensure they are always performing at the required level of accuracy. A Terrestrial Laser Scanner is one such instrument and with the vast amount of information that this machine is able to capture, it is especially important to run regular accuracy checks. This research is building on the work that has been done by previous researchers on the assessment of instrument accuracy and the establishment of facilities specialized for this assessment. Theoretical principles are investigated in the form of Least Squares Adjustments, similarities to panorama photography and photogrammetric accuracy. Terrestrial Laser Scanners are reviewed with respect to their scanning principles and data acquisition. The methodology incorporated in this research encompasses the positioning of targets, their survey to establish high accuracy coordinates through various methods of adjustment and thereafter the scanning of those targets. Comparisons were done using derived angles and distances between the targets to discover the point accuracy of the Laser Scanner. This was done for two facilities; a short range facility (1 to 15 meters) and a medium range facility (1 to 75 meters). The medium range facility also included a range testing baseline for distance accuracy assessments. The outcomes from the comparisons between the surveyed control data and the laser scanner observed data indicated that the laser scanner is performing below the accuracy of the surveyed data. The laser scanner was further compared against the manufacturer quoted performance specifications and revealed the laser scanner to be performing below the quoted values. The laser scanner in question showed stronger results in the horizontal measurements over the vertical measurements. All results suggested the laser scanner was delivering weak results in the vertical observations due to a mis-alignment of individual scan halves. This research was able to establish two accuracy assessment facilities specialized for Terrestrial Laser Scanners under these same conditions. Both facilities were used in conjunction, to analyze the Z+F Imager 5010C laser scanner and determine the point accuracy in terms of the observed angles and distances from this machine. The results are also able to identify errors in the performance of the laser scanner and whether or not it is performing within the manufacturer specifications by noticing any large values such as in the case of the vertical observations for this instrument.
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Measuring tenure security of the rural poor using pro-poor land tools: A case study of Itaji-Ekiti, Ekiti State NigeriaBabalola, Kehinde Hassan 21 February 2019 (has links)
The sustainable development goals aim to improve the lives of rural dwellers by ensuring the security of tenure of the rural poor. This led researchers and nongovernmental organisations to investigate the security of tenure of the urban and rural poor in developing countries. To improve the security of tenure of the rural poor, many developing countries have initiated programmes that encompass reform of land tenure and land administration systems. To provide a solution to the insecurity of tenure, researchers and non-governmental organisations developed pro-poor land tools to address the gap created by the formal land administration system. To test the developed land tools, researchers apply them in selected case study areas. This study investigates and analyses the tenure security of the rural poor of Itaji-Ekiti, Ekiti State, Nigeria. The New Continuum of Land Rights Model (NCLRM) and the Social Tenure Domain Model (STDM) were applied to land rights types found in the case study. Techniques, theories and tools used were based on a single case study methodology. The mixed methods approach was used to analyse and evaluate the tenure situation in Itaji-Ekiti. This yielded an in-depth understanding of the case. The research further examines critical areas of the Land Use Act of 1978 using the conceptual framework for understanding cadastral system development in customary land rights context. The mixed methodology approach was used in analysing the vital areas of the Act. Land professionals, civil servants and students were the target group that contributed to the study. The research findings showed that security of tenure is weak because every land rights types found in Itaji-Ekiti can be affected by conflicts with customary and informal tenure. The results of this research showed that the Land Use Act is effective in some areas and dysfunctional in others. This is attributed to the age of the Act and many sections of the Act that are not pro-poor. The implementation of the Act showed that it is effective in urban areas while it is not solving land-related problems in rural areas. The research further revealed that the use of case study methodology using mixed methods are suitable for measuring tenure security of the rural poor. The findings provide an understanding of the current land policy in Nigeria and as well as understanding land tenure insecurity in Itaji-Ekiti. The research also provides information for researchers in the field of cadastral system research on the use of propoor land tools as alternative approaches to recording land rights and measuring tenure security of the rural poor.
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Elements of design for indoor visualisationGangraker, Muhammad Zaid January 2016 (has links)
Indoor visualisation has received little attention. Research related to indoor environments have primarily focussed on the data structuring, localisation and navigation components (Zlatanova et al., 2013). Visualisation is an integral component in addressing the diverse array of indoor environments. In simple words, 'What is the most efficient way to visualise the surrounding indoor environment so that the user can concisely understand their surroundings as well as facilitating the process of navigation?' This dissertation proposes a holistic approach that consists of two components. The significance of this approach is that it provides a robust and adaptable method in providing a standard to which indoor visualisation can be referenced against. The first component is a theoretical framework focussing on indoor visualisation and it comprises of principles from several disciplines such as geovisualisation, human-perception theory, spatial cognition, dynamic and 3D environments as well as accommodating emotional processes resulting from human-computer interaction. The second component is based on the theoretical framework and adopts a practical approach towards indoor visualisation. It consists of a set of design properties that can be used for the design of effective indoor visualisations. The framework is referred to as the "Elements of Design" framework. Both these components aim to provide a set of principles and guidelines that can be used as best practices for the design of indoor visualisations. In order to practically demonstrate the holistic indoor visualisation approach, multiple indoor visualisation renderings were developed. The visualisation renderings were represented in a three-dimensional virtual environment from a first-person perspective. Each rendering used the design framework differently. Also, each rendering was graded using a parallel chart that compares how the different visual elements were used per the rendering. The main findings were that the techniques/ renderings that used the visual elements effectively (enhanced human-perception) resulted in better acquisition and construction of knowledge about the surrounding indoor environment.
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Towards a geoid consistent vertical datum in South AfricaMphuthi, Matthews Siphiwe 07 March 2022 (has links)
Traditionally, vertical datums have been realised through mean sea level (MSL) data, at one or more tide gauge station(s), followed by a precise levelling procedure to establish a network of benchmarks. Most countries around the world are still using mean sea level based vertical datums, and South Africa is not an exception. However, these vertical datums suffer from a myriad of problems such as; numerous errors from the levelling networks and tide gauge sea level measurements, high cost of maintenance and upgrade, instability due to high MSL variability, inconsistency with data acquired by satellite and space-based measurement instruments and techniques, just to mention a few. Therefore there is a need to establish a geoid-based vertical datum to mitigate the limitations of mean sea level based vertical datum and to open further frontiers in geodesy, geophysics and geodynamics research, and related applications. Establishment of a national geoid-based vertical geodetic datum requires critical studies on the existing national height system(s) and related distortions, appropriate height system and related reference surface, offset between a local height datum and the intended reference surface, among others. The world is moving towards global unification of vertical datums to modernise the vertical positioning technique, an international height reference system (IHRS) would provide a globally unified height reference system. The horizontal positioning is already realised on the international terrestrial reference frame (ITRF) with high precision, and a similar approach for the realisation of a new vertical datum for South Africa is required. This study carries out analysis on the following aspects over South Africa: comparison between spheroidal, orthometric and normal height systems; accuracy of levelling network; vertical datum offset in relation to geoid, quasigeoid and the IHRS. It concludes by providing a unique framework for establishing a geoid-based vertical datum in South Africa. A numerical investigation of the correlation between the South African spheroidal, orthometric and normal height systems is conducted. It is determined that the spheroidal orthometric height system is more correlated with the normal height system (~ 21.3 cm on average) than the orthometric height system (~ 40.7 cm on average). A further numerical assessment was conducted to determine the magnitude of misclosures and the empirical value for the first order levelling network on the levelling loops. It was determined that majority of the levelling loops fall within the acceptable empirical value for the first order levelling network (c = 0.003). However, only one levelling loop does not fall within the acceptable range of misclosure for the first order levelling network, with a misclosure from spirit levelling measurement of −10.2 cm while the estimated acceptable misclosure is 9.7 cm. The vertical datum offset between the South African local vertical datum and global vertical datum was achieved by estimating the vertical datum offset and the geopotential values on the four fundamental benchmarks. A single-point-based geodetic boundary value problem (GBVP) approach was used following Molodensky's theory for estimating the height anomalies from the disturbing potential using Bruns's formula. The gravity potential at each tide gauge benchmark (TGBM) in South Africa deviates from the potential of the global reference surface by 0.585, −2.023, −2.597 and 2.105 m!s"! for Cape Town, Port Elizabeth, East London and Durban tide gauge benchmarks, respectively. The corresponding vertical datum offset between the international height reference system and the four fundamental benchmarks over South Africa are 5.973, −20.647, −26.518 , and 21.496 cm for Cape Town, Port Elizabeth, East London and Durban tide gauge benchmarks, respectively. The datum offsets between the land levelling datum (LLD) and the global vertical datum has been estimated, for the first time over South Africa, in this study. A preliminary geoid-based vertical datum in relation to the IHRS for South Africa was determined and evaluated using 138 GPS/levelling data points distributed over the country. However, since it would be difficult to identify exactly which data points are associated with a particular TGBM, the TGBM in Cape Town was held fixed for this analysis. During this analysis, the spheroidal orthometric height was unified to the IHRS (5#$%&#), an existing bias between the 5#$%&# and the local quasigeoid is estimated to be approximately 15.8 cm on average. An adequate data coverage is required to improve the quality of the determined vertical datum offset for the South African vertical datum in relation to the global vertical datum. It is proposed in this study that a normal height system should be adopted for South Africa, with the relevant reference surface being quasigeoid model. Some considerations to be taken during the implementation and adoption of a consistent geoid-based vertical datum in South Africa are discussed.
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Integrating a web-based GIS in the optimization of the customer connection process for utility company: A case of Kenya Power; Lighting Company, Ltd.Munywoki, Margaret Ngeli 08 March 2022 (has links)
Great strides have been made world over in the use of GIS as a tool for the management of resources and decision making in the utilities. Utilities are now integrating GIS with other company systems in a bid to reduce operational costs, maximize revenue as well as improve efficiency and care to customers. However, this use has been confined to ensuring optimised service delivery to existing customers and overlooks new prospective customers. With privatization and deregulations, utility companies are now faced with a new challenge to strive for the market share in the most efficient and cost-effective ways. This research sought to develop a complementary web-based GIS application that can be integrated with existing utility company systems to improve efficiency in the new customer connection process. Waterfall System Development Methodology (SDM) was adopted in this research. Its simplicity and straightforwardness gave it a niche over other SDMs in-terms of implementation as one only moved to the next stage once the previous stage had been fully completed and tested. Digital online map, counties information data, enquiry for supply forms as well as the supply contract forms were used as the main datasets in the study. The objectives of this research were achieved by the development of a geodatabase to record, store and retrieve customer information; and a web-based GIS application to facilitate recording and upload of this information. It is possible to develop a web based GIS application that can be integrated with existing company's systems. Through integration, the system will automate and augment most of the manual processes in the new connection work-flow. This development would greatly improve new customer connection efficiency, maximize revenue collection for the utility and elevate the customers' socio-economic statuses. The system would also provide a platform for the monitoring and analysis of the infrastructure development geared towards the achievement of Kenya's Vision 2030.
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3D property objects in South African local government: the necessity of representing and managing the third dimension in the City of Cape Town property management systemHumby, Lara 16 February 2022 (has links)
The objective of this research was to analyse whether there is a need for a form of 3D Land Administration System (LAS)in South Africa (SA) based on the land administration functions of land tenure, land use, land development and land value. The investigation can be divided into two key focus areas that align with subsystems of the LAS: (i) the Land Tenure System (LTS) that is responsible for land tenure; and (ii) the Property Management System (PMS) that is responsible for land use, development and value. These two key areas fall within the SA LAS and make use of the cadastre as a foundation. Humby (2014) focussed on the first subsystem and found that there may be a significant need within the LTS for a 3D cadastral record or a 3D legal property object (LPO). The second subsystem is the focus of this study. To analyse the need for 3D in the PMS, the City of Cape Town (CCT) was adopted as a single case study, and modelled using systems thinking tools. The model focussed on the definition, use and management of property information, or the conceptual 3D property management object (PMO), to fulfil the land administration functions of land use, development and value within the CCT PMS. Established land administration theory, including the Land Management Paradigm, the good governance principles and RRR requirements, was used as a foundation against which the CCT PMS was analysed. This allowed for an increased understanding of the current CCT PMS's ability to achieve its land administration goals, policies and sustainable development. Following this, the current use of 3D within the CCT PMS was presented and analysed, along with the potential resulting benefits, uses and challenges of introducing 3D into that system. Semi-structured in-depth interviews, documentation evidence and participant and direct observations were employed in this section of the research. Furthermore, international land administration and 3D experiences, as presented in the literature review, were incorporated in this analysis. This study concludes that introducing a third dimension into the CCT PMS would have its challenges, but the uses and benefits that have been seen globally and that are recognised within the CCT, may outweigh those challenges. The research illustrates how a 3D Property Management Object would clarify the records and aid the land administration functions. Preferably, 3D would be introduced into the cadastre and LTS initially, and the PMS could then adopt that real RRRs LPO record as a foundation for the PMO records. However, the LTS has fallen behind in technology and it appears the CCT PMS will have to take the lead in introducing 3D into the SA LAS. It is recommended that a full cost-benefit analysis is conducted prior to any further research or development within the CCT.
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Towards a new South African geodetic datumNewling, M January 1989 (has links)
Bibliography: pages 134-140. / The overall scale and orientation of the South African trigonometrical readjustment will depend both on the traditional distances and azimuths and on TRANSIT Doppler observations. The traditional observations are used to compute the relative positions of points within the control network. TRANSIT Doppler observations, as well as giving relative positions, can be used to determine absolute co-ordinates (in a global reference system) with an accuracy of about one metre. One purpose of the present study is to present a way of combining the various Doppler observations to the TRANSIT satellites and to derive a single set of geocentric co-ordinates for the stations at which Doppler observations were recorded. Little work has been published concerning the combination of such Doppler observations. Having arrived at a set of geocentric co-ordinates, in order to use them in the horizontal adjustment, they must be transformed to latitude, longitude and height with respect to a defined ellipsoid. The second purpose of the present study is to examine various criteria for choosing such a datum and thereby make a suitable datum selection. There are various ways of processing observations to the TRANSIT satellites; these techniques along with the rest of the Doppler system are described in chapter 3. Chapter 4, which contains the bulk of the work in the present study, addresses the problem of the unification of Doppler subnets into a single geocentric network. Chapter 1 contains an introduction and gives a brief overview of the various reference systems used in Geodesy while Chapter 2, which is largely historical, describes the existing geodetic network in South Africa, particularly the Cape Datum on which this network is computed. In chapter 5, using the co-ordinates for the Doppler stations derived in chapter 4, various criteria are considered for the selection of a datum on which to carry out the readjustment and recommendations are made for a replacement South African geodetic datum.
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Mathematical and numerical methods in satellite gravity gradiometryMusa, Ahmed January 1998 (has links)
No description available.
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A way to use GIS (incl. geomasking) to understand homelessness: a focus on the spatial characteristics of and around sleeping locations of the homeless in Cape Town City BowlKekana, Dime 13 September 2020 (has links)
Background: The homeless individuals/groups are the most vulnerable and less dignified member of the society. The evidences lie in the nature of their sleeping locations in the urban spaces, amongst other aspects. An internationally unique and integrated approach (GIS/socio-spatial) is utilized to enhance the knowledge and understanding of homelessness through analyzing the spatial characteristics of and around the sleeping locations of the homeless community in the urban public spaces, Cape Town City Bowl (South Africa) case study. Data Source and Method: Through the quantitative approach, the individual sleeping locations of The Homeless, including their surrounding characteristics, are observed daily for two weeks, 13-26 Oct. 2018 (total of all locations: n = 9515, daily average, n = 680) between 06:00 am and 08:30am. The analyses entail sequential application of eight analytical methods; spatial distribution, attribute analysis, proximity analysis, weather analysis, and obfuscation/geographic masking Results: (a) The daily individual sleeping locations of the homeless individuals and groups increase over time but their geographic distributions are similar or display insignificant/little variations. (b) Majority of these locations are situated in marginalized urban spaces that deny The Homeless personal privacy/security, human dignity and perpetuate stigmatization and social isolation. (c) The sleeping locations of The Homeless are far from the sources of basic needs to enhance their livelihoods (e.g., water resources). (d) Although more data is needed, however, the limited data in this research show that weather conditions are (in)directly related to the changes in the numbers of sleeping locations. (d) The voronoi masking and weight rand perturbation are best presenting the sleeping location of The Homeless without compromising the spatial confidence of The Homeless, and the spatial distributions/patterns of these locations. Conclusion: GIS (geographic information system) is capable of enhancing the knowledge and understanding of homelessness, and therefore, it can inform establishments and improvements of initiatives/measures that seek to reduce the vulnerability of the homeless community and/or integrate them with the public community, especial in the urban spaces.
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