Land Surveying

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Evaluating cadastral systems in periods of uncertainty: a study of Cape Town's Xhosa-speaking communities.
(1999) Barry, Michael Brendan.; Fourie, Clarissa.
Evaluating the effectiveness of a cadastral system in situations where the social, political and economic environments are volatile and there is uncertainty over whether the cadastral system is likely to be used in the manner intended by the authorities remains a priority in developing countries. South African society, having negotiated a new democratic political dispensation in the early 1990’s, has been experiencing fundamental social and political change. In this context, the experimental focus of this study is on analysing effective cadastral system usage by people who were previously excluded from owning land in urban areas. The study explores the effectiveness of the existing cadastral system in addressing the wants of Xhosa-speaking communities in Cape Town during this period of substantial change. There is a paucity of substantive and methodological theory to evaluate a cadastral system in an uncertain, unstable situation. Based on soft systems theory, strategic management theory and existing cadastral theory, a conceptual framework to understand a particular situation has been developed. Using this conceptual framework, and drawing on the theory of planned behaviour and a social change model, an evaluative framework has been created that is germane to the South African situation. The primary focus of the empirical work in this study was on usage of the system of cadastral boundaries and the land registration system. A set of four case studies that includes an informal settlement, two site-and service schemes and a suburb where much of the land is held in private ownership were studied. These case studies were augmented by a study of a large area that is predominantly Xhosa-speaking in Cape Town’s eastern metropole. The conceptual and evaluative frameworks and the methodology adopted to conduct this research were found to constitute valid substantive and methodological theoretical foundations for studies of cadastral systems and land administration systems. In the context of the empirical work conducted, it is concluded that in Cape Town’s Xhosa speaking communities, in a stable situation where a favourable environment encourages its usage, the existing cadastral system will be effective and used in the manner intended by government. In volatile, unstable situations, the cadastral system will not be fully utilised for a variety of reasons. One reason being that in a rapidly changing social and political environment the land administration authority may not be able to govern effectively, and at the same time factions within a settlement may manipulate the land tenure rules to suit their own objectives. In such situations, conflict is inherent and natural in the relationship between the authorities and the community within a particular settlement and in the relationship between factions within that community. However, in this study it was found that in these uncertain situations that although cadastral instruments and processes were not used to effect all transactions in land, they form the essential core of a range of systems that are used to affirm an individual’s claims to rights in land. Moreover, in cases of conflict over land rights, the official records and surveyed cadastral boundaries constituted the point of departure in all negotiations.
Understanding the inter-relationships for the creation of a local land information system : the Zimbabwean local government experience at growth points.
(2000) Zhou, Samson Zigah.; Fourie, Clarissa.
Zimbabwe is made up of eight provinces, fifty-seven districts and as many Rural District Councils. In each district there is at least one Growth Point although some may have up to two or more. A Growth Point is a 'town or City in the making' and is usually, but not necessarily the capital of a district. Rural District Councils, which form the local administrative authority and have administrative responsibility over the land that falls within their jurisdictions, are often located at these Growth Points. These local authorities liaise and interact closely with central government, which is made up of Ministries and Departments with different functions, which somehow hinge on the administration of the land. This makes the linkages and land information flows, based on land records crucial. The legacy of the history of separate development introduced and left systems of government, which are complex and hinder a free flow of information within central government and also between central and local governments. These linkages and interrelationships are mapped and traced with a view to streamlining information flows in order to eliminate or minimize flaws . While the efforts of decentralisation towards this goal are recognized, the shortcomings have been cited and the thesis makes some recommendations based on a research undertaken with the cooperation of Gokwe Rural District Council at Gokwe Growth Point. The thesis recommends strengthening the local capacity by assisting their efforts to computerise their records and eventually develop that into a fully integrated local Land Information System that should eventually be linked to the National System.
The role of the geomaticist in natural resource management.
(2000) Fifield, Simon Peter.; Fourie, Clarissa.; Forbes, Angus Mcfarlane.
The essence of this thesis may be described by Ruther's argument that the survey profession is confronted with the necessity of having to redefine its role in society, or face the consequences of having the profession become marginalised (n .d: 1). The thesis reviews the functions of a traditional land surveyor, and shows how these functions are diminishing. This is done to illustrate the need for change in the profile of a traditional land surveyor, and the necessity of him redefining his role in society, in order to prosper in the future. The concept of geomatics, as an integrated approach to the acquisition and management of spatial data is introduced, and is used to illustrate the types of skills which a traditional land surveyor already has, and would need to acquire, in order to make the transition to a modern land surveyor, or what is tenned a geomaticist. A case study is then carried out in order to test the validity of the conceptual framework.
The Lesotho geodetic control network.
(2001) Matela, Motlotlo P.; Jackson, Jonathan.
The Geodetic network of Lesotho as established by the Directorate of Overseas Surveys in the 1950's, has been known to have distortions of several meters in some areas. This network is still very much in use today. Several altcmpts were made to strengthen the DOS network. but these attempts were not used for a complete readjustment. The South African Control net, which completely surrounds Lesotho, has recently been readjusted so as to bring it into sympathy with the WGS reference system used by GPS. It has become urgent to similarly update the Lesotho control system, to enable economical use of GPS surveying methods. This thesis addresses the problems of updating the Lesotho control system and also of bringing existing data onto the updated systcm. This thesis first reviews the historical background of Lcsotho and that of its geodetic net work. Different sets of data were collected and common points in the compared sets selected for the analysis. The South African readjustment was chosen as the standard, because it is the most recent, derived with the support of the new zero-order South African control net. The data sets were fitted to the reference system using conformal transformations from first up to fourth order. These comparisons were used to detect outliers. They revealed systematic distortions in the older data. which could be largely eliminated in the fourth-order transformation. The opportunity to update control point co-ordinates also gave an opportunity to revisit the existing choice of using two map panels of the Gauss Conform projection. The distortions involved in using a single Gauss Conform panel and also the UTM projection were investigated. A companson or all the methods and the recommendations concludes the section. Software was developed for transforming existing survey data onto the recommended updated reference system. The height system used in Lesotho is also reviewed because it forms part of the control net. The focus is on heights in relation to gravity. because that bears on the relation of published orthometric heights. with GPS-derived ellipsoidal heights. This section is mostly a literature review, starting with the theory of heights and gravity, proceeding onto the applied corrections and then showing what relations have been found.
Applications of land information systems in land re-adjustment projects : "Lesotho experience".
(2001) Mothunts'ane, Bophelo.; Chilufya, Sexton Mwitwa.
Land information is a an important resource in planning, and in undertaking land administration functions such as allocation of interests to land, land adjudication, land valuation, physical planning, etc. Rapid urbanization, however, puts great pressure on personnel delegated to undertake these functions. The personnel can no longer cope with capturing, processing and disseminating land information for the increasing urban population. Observing the failures of land information management to cope with rapid urbanization, the researcher undertook an exploration into the capabilities of LIS to manage land informatioo for The Millennium Park Land Development Project (MPLDP) in Maseru, the Lesotho capital. The project is based on land readjustment principles and is of mulli-stakeholdership. Such big and networked projects have been shown to be associated with land information management problems. Undertaking this research was motivated by many success stories however, world wide, in which LIS was introduced as a tool to assist in land information management. The main themes in this project are firstly, the study of Land re-adjustment as a land management technique to meet land demand for urbanization and secondly land information system as a tool to manage land information for a land re-adjustment project. Study of LR will help understand what land information is required for such a land management project. Study of land information system will help exploring its capabilities that can be applied to manage land in formation for LR projects. Furthermore, as a case study to this, the MPLDP system is analysed. examining the activities and ways in which land information is managed. This analysis is aimed at identifying the constraints that result in the observed back logs in the project activities; and recommending improvements. Many problems and constraints are identified in the MPLDP. As a land surveyor, only improvements related to technical constraints are considered in this research, with cognizance of the legal and institutional issues that need to be addressed in implementation of these improvements. The main improvement discussed is the creation of automated databases and illustrations are given on how these databases could be used to manage land information effectively for the MPLDP.
The development of a local land records system for informal settlements in the greater Edendale area.
(2001) Cowie, Trevor Allen.; Fourie, Clarissa.
This dissertation examines the various forms of informal settlements in evidence in the Greater Edendale Area, and extracts the design criteria for the development of an appropriatc land records system to manage these informal settlements and their upgrading processes. It is shown that the various setllement patterns in existence ill the Greater Edcndale Area (GEA) reflect the apartheid history of South Africa and the policies of the previous governments. All exhibit certain aspects of informality, and therefore exist at various points on a continuum of formality-informality. Certain settlement patterns, such as the properties within formal townships developed by the former Department of Development Aid, possess many formal aspects and relatively fewer informalities, whereas others, for example the conventional informal settlements on State owned land, are informal in almost every respect. It is shown that the government's policies require informal aspects of settlements relating to land tenure and services should be upgraded, and that the responsibility for such upgrading has been delegated to the local government level. I will show that this upgrading of informal settlements can be broken down into four major processes which make up the overall upgrading process. These are land delivery, land tenure reform, provision of services, and cost recovery. It is argued that to effectivcly deal with these upgrading responsibilities, the local government structure. in this case the Pietermaritzburg-Msunduzi Transitional Local Council , should develop and maintain a land records system at the local level, with community participation to ensure sustainability. The design requirements for such a system are identified throughout the chapters, and are drawn together in the final chapter as a set of design criteria for the land records system. These design criteria call be represented by five main themes: firstly, that the land records system should be based on the design of the multipurpose cadastre; secondly, that in addition, it should accommodate non- parcel-based tenures; thirdly, that it should incorporate temporal GIS technology; fourthly, that it should be easily accessible to the community; and finally, that it should incorporate the users' needs and should be extremely user-friendly.
A framework for applying spatial decision support systems in land use planning.
(2002) Peacock, Peter Graham.; Chilufya, Sexton Mwitwa.; Fourie, Clarissa.
For local authorities to manage land policies effectively data bases of land use information that are current and mirror development on the ground are required. At present local authorities have no mechanisms in place to acquire maintain and spatially link land use information. Detailed land use information is not generally available at the local level. Generally little attention is paid to maintaining the expensive data which is assembled when planning schemes, development plans or projects are prepared. Land use planning has traditionally focussed on the control rather than the facilitation of development. Details of the actual land use on the ground are generally ignored as tariffs for tax purposes are set on the zoning of the land or a flat rate rather than the actual land use. This lack of land use information, which is exacerbated by informal settlement, causes delays in approving new land uses. There is generally no data available for informal areas and land use and tenure is subject to the informal rules that have evolved with such settlements. If these areas are to be included in the formal land management systems, ways of including and maintaining land use information about these settlements must be developed. By reviewing land information theory, the South African legal land development framework and using a small town as a case study, I have shown that provided certain conditions are met a Spatial Decision Support System (SDSS), designed to record and maintain the land use data necessary to support land use planning in both formal and informal contexts, could be a valuable land management tool. Such a system should be implemented in partnership with local communities and should; • support local level land use decision making and regulation • serve as a land management tool to integrate formal and informal communities • have mechanisms to keep land use information current • be transparent about the type of land use information • develop linkages with regional government to provide detailed land information over time.
The development of selected learning units in land administration to facilitate the land reform programme.
(2003) Landman, J. C.; Fourie, Clarissa.; Jackson, Jonathan.
With the introduction of a new government in South Africa in 1994, the country embarked on a programme of land reform, and currently the process of dealing with the issues of Land Redistribution, Land Restitution and Tenure Reform is underway. Sound land administration is crucial to the Land Reform programme, and to future peace in the country. Such land administration requires a range of role players with varying levels of education. Also in the field of education the country saw a complete break away from the system of content-based education and competency based training, to one of outcomes-based education and training. The introduction of this new educational dispensation is overseen by the South African Qualifications Authority (SAQA), who is in the process of ensuring the smooth implementation of the National Qualifications Framework (NQF) into all aspects of learning in South Africa. The purpose of the NQF in the broad sense is to provide for the registration of nationally and internationally recognised qualifications on all levels in an integrated system, in order to facilitate access to and provide mobility in education and training. The NQF is designed to develop learning that is relevant to the needs of industry, the individual and the economy, but also to be dynamic and able to adapt quickly to changing circumstances. It therefore is providing South African educators with new challenges in the field of Outcomes-Based Education and training. One of the methods available to identify appropriate learner outcomes to meet the above requirements is the DACUM method, which works on the premise that expert workers are better able to describe/define their job than anyone else. The DACUM method is a proven way of arriving at relevant outcomes, which is the starting point in the curriculum development process as used in outcomes-based education and training programmes. In this thesis the DACUM model is tested as a tOGI for designing relevant outcomes, and such outcomes are modified in accordance with outcomes in practices in existing programmes in land administration in SouthernAnother important component in designing learning outcomes is to ensure that appropriate embedded knowledge is identified in order to avoid that learning becomes mechanistic without learners mastering necessary content. In this thesis a body of general knowledge has been compiled which can inform the curriculum developer on relevant embedded knowledge when designing learning units in Land Administration. This body of knowledge includes land related historical issues in South Africa as well as Australia and the USA, Government Policies and Legislation dealing with Land Reform. Finally some learning units in one of the fields in land administration were developed. In making the choice of which field, care was taken to identify one which will span a range of NQF levels, and the choice fell on the adjudication of land rights, which proved to have relevant learning on every NQF level from Level 3 to Level 7. To achieve this the writer had to interview a number of stakeholders and compile a body of knowledge specific to adjudication. Care was taken to develop elements, which could be used by the Standards Generating Body (SGB) in Surveying in designing Unit Standards, as well as by educators in Higher and Further Education. Africa.
A methodology for the capture and registration of land rights under the Communal Land Rights Act.
(2007) Weston, Alan C.; Jackson, Jonathan.
One of the major policy objectives of the South African government is to reform land tenure and address the current inequitable dispossession of land. A key to the successful implementation of land reform in communal areas will be the recently enacted Communal Land Rights Act. This Act allows communities to be vested with juristic personality, and enables those communities to acquire and hold rights, incur obligations, and encumber the land by mortgage in the name of the community. Communities will now have a legal tenure recognized by and enforceable at law. The Act provides the mechanism for replacing old order rights with new order rights, which, in turn, may be upgraded to freehold title with community consent. While the Communal Land Rights Act is clear in its approach to providing legal security of tenure, the implementation and linking of the internal land rights within these new legal collective ownership structures to the existing formal system is still uncertain. With the flexibility allowed under the Act, this dissertation offers a simple, cost-effective alternative for the registration of land rights using the envisioned Land Clerk of the Department of Land Affairs. This option involves placing suitably equipped Land Clerks into the communities in which they serve, operating as autonomous self-sustaining contractors. Research for this project was conducted in the community of Ekuthuleni (KwaZuluNatal), where two members of the community were equipped with a portable rig and trained to perform as Land Clerks. The author and others from the University trained them in the use of a computer, scanner, printer, handheld GPS receiver, and assorted software. In addition, to allow them to function autonomously, a photovoltaic power system was set up at their residence. To assess their ability as Land Clerks, several field projects were undertaken within the community. Under the guidance of the author, these field tests involved contacting individual landowners, capturing personal and property information, and registering that data into a specially written database programme. Evidence of previous land ownership was noted and rebristered, GPS coordinates were collected and registered in the process of delineating the landowner's property, and a form reflecting all captured data was printed for the landowner's records.
Change detection of invasive bracken fern (Pteridium aquilinum [L.] Kuhn) in the Royal Natal National Park and Rugged Glen Nature Reserve.
(2013) Singh, Kaveer.; Forbes, Angus Mcfarlane.; Akombelwa, Mulemwa.
Bracken fern (Pteridium aquilinum [L.] Kuhn) is an indigenous invasive plant and it is known to have a negative impact on biodiversity. This research focuses on infestations of bracken fern in two areas within the uKhahlamba Drakensberg Park World Heritage Site; the Royal Natal National Park and the Rugged Glen Nature Reserve. Prior change detection research on bracken fern were constrained due to the low resolution satellite imagery and the inability of hard classification techniques to account for the mixtures of land cover types that occur within pixels of low resolution imagery. To overcome these constraints this research applied the fuzzy image classification technique to multispectral digital aerial imagery of 0.5 m spatial resolution. Multi date imagery used for image classification was captured in the mid-winter of 2009 and mid-spring of 2011. Thereafter post-classification change detection analysis was conducted using the fuzzy classified images. The classified images were verified using ground truth surveys. The 2009 and 2011 fuzzy classified images produced overall accuracies of 81.4% and 94.4% with Kappa coefficients of 0.63 and 0.89 respectively. This research found that the distinct seasonal development pattern of bracken fern and the time of year imagery were captured were significant factors in its detection. As bracken fern was found to be more spectrally distinct in spring as compared to winter, due to the plant growth of bracken fern, grass and other shrubbery. These classified images were used in post-classification change detection analysis which revealed that the bracken fern infestation in the Royal Natal National Park and Rugged Glen Nature Reserve had increased at a rate of 24 % and 27 % per annum respectively. This showed that bracken fern is spreading in the Royal Natal National Park and Rugged Glen Nature Reserve, as expected. Fire regimes, slope and aspect were found as factors that could be promoting the spread of bracken fern, 67.5 % and 75 % of the bracken fern infestation in the Park and Reserve respectively, occurred in areas that were burnt by fire regimes and have gentle to moderately gentle slopes facing east, south east and south.
Exploring the spatial expansion of settlements in customary regions : a case study of Adams rural, KwaZulu-Natal.
(2015) Dlamini, Siboniso Msinsi.; Akombelwa, Mulemwa.; Chilufya, Sexton Mwitwa.
Adams Rural is one of KwaZulu-Natal’s customary regions which falls under the traditional boundaries of the Ingonyama Trust Board. In this rural area traditional customs are still being practiced. The major land use was previously dominated by agriculture and very few residential settlements. This study reflects on the increasing recognition of the expansion of human settlements in this customary region. The expansion of human settlements is observed to have increased over the past decade and is confirmed by annual aerial imagery of the area captured by the eThekwini Municipality. The historical images captured by the National Geo-Spatial Information (NGI) suggest that there has been a substantial land use change in the area, resulting in loss of land previously used for sugarcane plantation. Therefore the study utilised spatial analytic techniques to quantify spatial changes in Adams Rural and map the land use / land cover change between years 2001-2004, 2004-2006, 2006-2008, 2008-2010 and 2010-2012 in Adams Rural. The research employs a post-classification change detection technique performed on selected orthophoto imagery, to assess spatial change patterns, to quantify the amount and the rate of change in human settlements of Adams Rural during the period 2001 to 2012. The results show that spatial extent of human settlements has more than doubled with commensurate loss in agriculture. Demographic data for 2001 and 2011 obtained from Statistics South Africa (Statistics SA, 2001 and 2011) also confirms that the population of the area has more than doubled over the same period. The rate of increase in settlements varied between periods considered with the population increasing proportionately. A closer inspection of the area was conducted using a questionnaire administered to the community. The questionnaire shows that the major contributor to the population increase in the area is the majority of people relocating from urban areas to this customary region. The questionnaire results further show that people are attracted to the development occurring in the area, larger parcels extent and the low cost of living with no bond payments, as there are no property rates payable on customary land. An attempt was made to project the spatial growth of built-up areas over the next 10 years using the change rate obtained from change detection verifying the prediction using the results from a questionnaire survey of the residents in the study area. It is observed that change by 2022 may likely follow the trend in 2001-2012. The present study shows that spatial analysis based on land use mapping using orthophoto imagery is very effective in monitoring the spatial features in customary regions.
Investigating the feasibility of establishing a South African marine cadastre.
(2015) Reddy, Kovilen.; Akombelwa, Mulemwa.; Chilufya, Sexton Mwitwa.
Human interaction with the marine environment is increasing at a rate at which marine management systems cannot keep pace. The land cadastral systems are deemed to be well-established and understood thanks to hundreds of years of development. Meanwhile, as marine technological innovations advance and population density in coastal areas grows, human interaction with the oceans is evolving, making existing systems in place for their management seem out-dated. In South Africa, the declaration of Project Phakisa to unlock the oceans economy, which has been relatively untouched, acknowledges the potential benefits that can be extracted from the sea. A land cadastral system consists of graphically depicted boundaries that have been surveyed, and a register that assigns any rights, restrictions and responsibilities to the area enclosed by such surveyed boundaries. Management of marine property rights is not dissimilar to the land cadastre insofar as there being parallel survey and registry components. Internationally, marine cadastre initiatives are being researched and implemented to update marine management systems while there is recognition for convergence of land and sea based spatial data infrastructures. This study explores the need for the development of a seamless cadastre across the land-sea interface for South Africa by assessing the perceptions of stakeholders that deal in land and/or marine environments. The study investigates access to land versus marine spatial data, legal and technical aspects, components and features of a possible marine cadastre. By adopting a case study strategy using both qualitative and quantitative inquiry approaches, the rendered results presented later in the dissertation have increased reliability resulting from the processes of data triangulation. The main findings indicate that the spatial and accompanying registration component of the land-based cadastral system is sufficient to form the cornerstone of land administration in SA. The literature review and canvassing of persons related to the geospatial fraternity indicates, via analysis of a questionnaire and interviews, shortcomings in good ocean governance. Although a marine cadastral system is feasible for SA, it is beset with spatial, technical, legislative and institutional issues that need ironing out. The unification of the land and possible marine cadastral systems would enable a single land-sea spatial data infrastructure that would mute the effects of an uncertain land-sea interface.
Seismic risk evaluation for the eThekwini Municipality Area.
(2015) Ramirez, Jennifer Eliana Martinez.; Singh, Moganavelli.; Akombelwa, Mulemwa.; Chilufya, Sexton Mwitwa.
Abstract available in PDF file.
Characterization and development of optical components for the Cassegrain telescope and laser beam coudé path of the lunar laser ranger of HartRAO.
(2015) Nkosi, Nokwazi Purity.; Combrinck, Ludwig.; Akombelwa, Mulemwa.
The Observatoire de la Côte d’Azur (OCA) donated a 1-m Cassegrain telescope to be used for the dual satellite and lunar laser ranging system currently under development at the Hartebeesthoek Radio Astronomy in South Africa. As the very first of its kind in the Southern Hemisphere, the new system will be designed and developed as a permanent lunar laser ranging system with high precision laser and electronic equipment to achieve millimetre accuracy. Limited technical details of the telescope exist so tests were conducted to determine the optical characteristics and performance of the telescope and its mirrors. The optical performance of the telescope was validated through the analysis of transmission efficiency, structural efficiency and image quality. Spectroscopic measurements were conducted to determine the transmission efficiency of the telescope by taking into account all losses in light from the reflection of mirrors, transmission of lenses and the secondary spider central obstruction along the path of the proposed coudé optical path. A system transmission of ∼90% was obtained if a coudé path with no central obstruction is used. The primary mirror and its support structure was validated using finite element analysis software (ANSYS) to model the amount of deformation the mirror will experience under gravitational and external loading. Taking into account the lightweight nature (honeycomb structure) of the mirror, its material properties and multiple support mechanism, ANSYS was used to compute the gravity deformations experienced by the mirror as the telescope tracks from the horizon to zenith. The deformations when gravity acts along the axial support were in the range of 1/6th of the wavelength, which is below the maximum limit expected for such a structure at the given weight. In order to analyse the image quality of the system, an optical analysis software (OSLO) was used. Spot diagram analysis revealed coma as the dominant primary aberration in the system. The telescope is diffraction-limited for on-axis performance and yields a Strehl ratio of 0.78 for off-axis performance.
Seismic sources, seismotectonics and earthquake recurrence for the KZN coastal regions.
(2016) Singh, Mayshree.; Akombelwa, Mulemwa.; Maud, Rodney.
Historical earthquake information forms a critical dataset for seismotectonic investigations that can be used for seismic hazard investigations of hazardous and high rise structures and national seismic hazard maps. This study systematically interrogates historical earthquake data for the region from various sources in order to have a better understanding of the origins of the larger earthquakes. Several previously undocumented earthquakes were found that can supplement the national catalogue. Various sources are postulated as origins of these tremors namely local sources located in Mtubatuba and offshore sources like the Mozambique Channel. A seismotectonic model of the study region is also presented from an analysis of earthquake data, structural and kinematic systems. Geo-spatial data from geology, tectonics, regional geophysical anomalies, historical and instrumental seismicity and kinematics are considered. For what was once considered as a diffuse seismotectonic region with low levels of seismicity and where insufficient, uncertain and incomplete data existed – we now have datasets that are more complete and have higher levels of accuracy. Earthquake epicentres from both the historical and instrumental record as well as thermal spring localities correlate with old Jurassic faults. An assembly of a variety of datasets and studies are performed followed by a delineation of respective seismotectonic provinces. Earthquake recurrence parameters were assessed for the seismic provinces. Many of the provinces had insufficient seismic data to compute parameters. Improved seismic monitoring of the east coast region is required to better characterise the seismic risk. These results re-emphasize the need to better understand the coastal environment for seismotectonic characterization and to densify the seismic network towards the eastern coastline.
Evaluation of largis application in planning, acquisition and maintenance of utility servitudes : an Eskom case study.
(2016) Monamane, Ntombizodwa A.; Chilufya, Sexton Mwitwa.; Musonda, E.; Akombelwa, Mulemwa.
GIS has been used for quite some time by utility organisations while the demands for their services by the public have also increased exponentially. This has prompted many utility organisations to constantly review their systems in operation for any potential problems associated with their use in order to propose possible and suitable improvements necessary to maximize their production. This study evaluates the performance of Land and Rights Geographic Information System (LARGIS), a GIS based information management system employed by Eskom to manage its servitudes’ land rights information. LARGIS has been analysed in terms of its application to planning, acquisition, registration and maintenance of servitudes land rights information. Information on LARGIS was collected using a questionnaire administered to Eskom personnel that work with the system while interviews were used to obtain more information not obtainable from the questionnaire. Obtained information was analysed using a relational matrix of data sets and processes in order to identify subsystems making up LARGIS. Information flows and processes in each of the subsystems were then analysed using Data Flow Diagrams (DFD) supported by associated Data Dictionary (DD) so as to identify possible shortcomings in information flows and information processing. The information collected was also used to identify institutional, legal, economic and additional technical shortcomings. The study revealed that LARGIS had made a positive impact on the way Eskom previously managed its servitudes by using a single system to plan, acquire, register and maintain land rights associated with servitudes. However, the study also identified shortcomings for which recommendation have been proposed so as to make LARGIS much more responsive to Eskom`s demands for servitudes land rights information management.
Development of an integrated model and system to enable optimal efficiency of the HartRAO LLR signal path.
(2017) Ndlovu, Sphumelele Colin.; Combrinck, Ludwig.; Akombelwa, Mulemwa.; Chetty, Naven.
The Lunar Laser Ranger (LLR) system under development at the Hartebeesthoek Radio Astronomy Observatory (Hartford) in South Africa is being built to accurately measure the Earth-Moon distance (at 1 cm level) through the use of short laser pulses, a single photon detection system, an accurate timing system and other sophisticated components. This LLR system is unique in Africa and indeed in the entire Southern Hemisphere. The system utilizes a 1 m diameter optical telescope, which was donated to the project by the Observatoire de la Côte d’Azur of France. In this work, the author discusses the development of an integrated model that will be utilized to obtain optimal efficiency of the HartRAO-LLR system. The model is used to estimate the expected number of returned photons by considering a number of parameters which affects the laser beam pulses as they traverse the atmosphere from the LLR telescope to the Moon and back to the telescope. Factors such as the apparent Earth-Moon range, atmospheric extinction, laser beam characteristics, optical path efficiencies and others, affect the estimated (predicted by software) and actual (measured) number of returned photons for the HartRAO-LLR station. The estimated average signal return rate (which is dependent on a number of factors) of the HartRAO-LLR ranges between 0 to 12 photons per minute, which is in agreement with the available data from five globally distributed LLR stations. It also correlated with the estimated returns that were obtained using least squares parameter estimations. They were in agreement by an average difference of 0.00272. Our estimated signal returns are strongly affected by two-way atmospheric extinction (atmospheric and cirrus cloud transmissions), variations in the laser beam incident angle on the retroreflectors located on the Moon as well as the varying Earth-Moon range. A new parameter, named lunar reflectivity ranging between 0 and 1, was introduced in the link budget equation to consider the effects of Moon Phases on the returned photons. Modelling the returned number of photons and comparing these to the actual number received leads to an understanding of the effects of numerous variables on the total laser path efficiency. Total system efficiency can be improved as well, as particular atmospheric conditions will not allow LLR to be successful on certain days. For these days, the system can be utilized for other purposes such as maintenance or satellite laser ranging.
Investigation of the directional effect on low cost houses due to the 2014 Orkney earthquake.
(2020) Nqasha, Thando.; Singh, Mayshree.
The Orkney earthquake on the 5th August 2014 caused major damages to houses in Orkney and surrounding areas. A post field assessment was carried out to determine the amount of damage caused by the earthquake. The Khuma township near Stilfontein was the most affected area where more than 600 houses were damaged. The damage caused by the 2014, Orkney earthquake was made worse by the poorly constructed low-cost houses in Orkney and the surrounding townships (Khuma, Kanana and Jouberton). These houses were vulnerable to earthquake damage. This study sought to determine the effects of additional factors that contribute to earthquake damage such as: building excitation angle, exposure of building weak points to earthquake direction and building finishes. In this study, results show that building excitation angle, exposure of weak points and finishes either plastered or un-plastered can contribute to the damage and vulnerability of a building during an earthquake tremor. Buildings of excitation angles between 0° - 30° and 61°- 90° had more damages compared to houses that had an excitation angles of between 31°- 60° for all 3 townships (Khuma, Kanana and Jouberton). The excitation angle of 0°- 30° recorded the highest damage grade, followed by excitation angle of 61° - 90°. The least amount of damage was observed for the excitation angle of 31° - 60°. The reason for these effects was that for the excitation angle of 0° - 30° and 61° - 90°, two or more building walls were perpendicular to the earthquake direction hence the building becomes vulnerable to toppling. Furthermore, houses that had weak points (windows and doors) exposed to the line of sight from the epicentre had reported more damages than houses that have no weak point exposed to the line of sight from the epicentre. Buildings that were completed with plaster were more resistant to earthquake damage than buildings that were un-plastered. The findings in this study can used be to establish fundamental building vulnerability properties for low-cost developments which will help to improve the construction of low-cost houses and reduce their vulnerability to earthquake damage and protect human life.
Machine learning, classification of 3D UAV-SFM point clouds in the University of KwaZulu-Natal (Howard College)
(2020) Ntuli, Simiso Siphenini.; Forbes, Angus Mcfarlane.
Three-dimensional (3D) point clouds derived using cost-effective and time-efficient photogrammetric technologies can provide information that can be utilized for decision-making in engineering, built environment and other related fields. This study focuses on the use of machine learning to automate the classification of points in a heterogeneous 3D scene situated in the University of KwaZulu-Natal, Howard College Campus sports field. The state of the camera mounted on the unmanned aerial vehicle (UAV) was evaluated through the process of camera calibration. Nadir aerial images captured using a UAV were used to generate a 3D point cloud employing the structure-from-motion (SfM) photogrammetric technique. The generated point cloud was georeferenced using natural ground control points (GCPs). Supervised and unsupervised classification approaches were used to classify points into three classes: ground, high vegetation and building. The supervised classification algorithm used a multi-scale dimensionality analysis to classify points. A georeferenced orthomosaic was used to generate random points for cross-validation. The accuracy of classification was evaluated, employing both qualitative and quantitative analysis. The camera calibration results showed negligible discrepancies when a comparison was made between the results obtained and the manufacturer’s specifications in parameters of the camera lens; hence the camera was in the excellent state of being used as a measuring device. Site visits and ground truth surveys were conducted to validate the classified point cloud. An overall root-mean-square (RMS) error of 0.053m was achieved from georeferencing the 3D point cloud. A root-mean-square error of 0.032m was achieved from georeferencing the orthomosaic. The multi-scale dimensionality analysis classified a point cloud and achieved an accuracy of 81.3% and a Kappa coefficient of 0.70. Good results were also achieved from the qualitative analysis. The classification results obtained indicated that a 3D heterogeneous scene can be classified into different land cover categories. These results show that the classification of 3D UAV-SfM point clouds provides a helpful tool for mapping and monitoring complex 3D environments.

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