Academic literature on the topic 'Geomatics'

Philosophiae Doctor - PhD (Post-School Studies)<br>This study is located in engineering education at a South African university of technology, and is theorised using relational ontologies such as critical posthumanism, feminist new materialism and non-representational theory. It explores the potential of a digital storytelling intervention in an undergraduate geomatics diploma programme. Geomatics qualifications in South Africa are critiqued for their embedded humanism and subtle anthropocentrism despite attempts at post-apartheid curricular reform. Additionally, these qualifications are focused on technical content, and heavily influenced by Western knowledges.

Nowadays, the world is facing disasters on an unprecedented scale: millions of people are affected by natural disasters globally each year and, only in the last decade, more than 80% of all disaster-related deaths were caused by natural hazards. Scientific predictions and evidence indicate that global climate changes are increasing the number of extreme events, creating more frequent and intensified natural hazards such as floods and windstorms. Population growth, urbanization and the inability of poor populations to escape from the vicious cycle of poverty are conditions to foresee that there will most likely be an increase in the number of people who are vulnerable to natural hazards, with a resulting increase of natural disasters and environmental emergencies. In recent years, international preoccupation for disasters and their impacts has intensified and risen closer to the top of the development agenda. For many years, response to disasters was largely confined to emergency relief and short-term life-saving actions. But over the last two decades, the critical importance of disaster preparedness, mitigation, and prevention has been widely recognized. The humanitarian and the United Nations system are therefore called to intensify their efforts to improve their capacity in order to provide support to the countries in need and to be better prepared to intervene. Such request came, amongst others, from the UN General Secretary in various occasions. In the frame of humanitarian operations, the World Food Programme (WFP) of the United Nations is in the front line. The WFP is the biggest UN Agency and responds to more than 120 emergencies per year worldwide. According to the UN reform, WFP is also the leader of logistics for UN and international bodies during emergency response operations. WFP initiated a process to reinforce its capacity to be a leading force in the area of emergency response, improving its Information Management capacity in support to emergency preparedness and response. To do so, an agreement of collaboration with the recently formed Information Technology for Humanitarian Assistance Cooperation and Action (ITHACA) Association has been signed and a joint collaboration started in February 2007. One of the objectives of the collaboration is about the use of Geomatics and Information Technology instruments in the Early Warning and Early Impact analysis field. Many worldwide experiences conducted in this area, show that the use of remote sensing and Geographic Information Systems (GIS) technologies, combined with up-to-date, reliable and easily accessible reference base geographic datasets, constitute the key factor for the success of emergency operations and for developing valuable natural disaster preparedness, mitigation and prevention systems. As a matter of fact, the unique characteristics associated with geographic, or geospatial, information technologies facilitate the integration of scientific, social and economic data through space and time, opening up interesting possibilities for monitoring, assessment and change detection activities, thus enabling better informed interventions in human and natural systems. Besides its proven value, the geospatial information is an expensive resource and needs to be fully utilized to maximize the return on investment required for its generation, management and use. Reuse and sharing of spatial information for multiple purposes is an important approach applied in countries where investment in spatial data collection and in their appropriate management has advanced on the basis of its known asset value. Very substantial economic benefits have been estimated by countries that have moved in the direction of optimizing data reuse. However, it is still relatively easy to find examples of projects and other development activities from around the globe that required expensive recapture of essential spatial data because they were originally captured in unique or non-standard file formats, or perhaps discarded after initial use. Recapture of data has also been undertaken in many cases simply because its prior existence was known only by its originators. The United Nations has not been immune to this problem, both within and between the multitude of entities that make up the Secretariat and its agencies, funds and programmes. Historically, the production and use of geospatial data within the UN entities has been accomplished by its component organizations, according to their individual needs and expertise. This has resulted in multiple efforts, reduced opportunities for sharing and reuse of data, and a unnecessary cost burden for the UN system as a whole. Thus, a framework data development approach has been considered necessary. This has resulted in the proposal that implement an UN Spatial Data Infrastructure (SDI). The term SDI is used to denote the relevant base collection of technologies, policies and institutional arrangements that facilitate the availability of and access to spatial data. A SDI hosts geographic data and attributes, sufficient documentation (metadata), a means to discover, visualize and evaluate the data (catalogues and Web mapping), and some methods to provide access to the geographic data. Beyond this, it will also host additional services or software to support applications of the data. The concept of developing a Spatial Data Infrastructure to fulfil UN data management needs was duly approved by United Nations Geographic Information Working Group (UNGIWG) members in 2005 at their 6th Plenary Meeting in Addis Ababa, in the context of a UN-specific SDI, or UNSDI. The WFP, like all other UN agencies, has been called to develop a Spatial Data Infrastructure, according to the UNGIWG recommendations. Therefore, during the last year the different units of WFP involved in the use of geospatial data worked at defining and implementing a WFP SDI with the aim of contributing at the whole UNSDI project. This effort was coordinated and supported by the ITHACA association. Aim of the study The objective of the conducted research has been to investigate the better solution for collecting and organizing geospatial data within a suitable geodatabase with two main purposes:  to support the WFP SDI effort: the development of consistent reusable themes of base cartographic content, known as Framework, Fundamental or Core Data, is recognized as a main and first ingredient in the construction of a SDI. Therefore, the definition of a geodatabase supporting all the WFP units dealing with GIS and geospatial data can be considered a fundamental and necessary step in the whole complex process of the development of the WFP SDI. Common used data provide key for the integration and, in the context of the SDI implementation, the definition of a Core Data geodatabase can be thought as one instrumentality to help improving interoperability, reducing expenses resulting from the inevitable duplications. Moreover, the major aim of the planned geodatabase is to supply all WFP users of a “minimum spatial dataset” which assures valuable geographic analyses and mapping, in support to decision makers during emergencies operations.  to support all activities carried out by ITHACA: the planned geodatabase must constitute a suitable instrument which realizes the integration and the organization of the large geospatial data needed by all ITHACA units in their activities, allowing their effective distribution, sharing and reuse, avoiding any duplication. Moreover, the implemented solution must also guarantee the correct management and updating of the data, keeping their integrity. Finally, this instrument must also allow the easy and fast sharing of necessary information produced by ITHACA during Early Impact activities with the WFP’s users engaged in the emergencies rescue operations. In conclusion, the major expected output of the study carried out, described in this thesis, has been the design and the development of a global database and of related rules and procedures in order to correctly store, manage, and exchange geospatial data needed either by WFP humanitarian workers and ITHACA users. The developed database solution allows integrating and updating globally consistent geographic data coming from different sources in many formats, providing each user with the latest datasets, thus avoiding duplications and mistakes. In methodological terms, the following procedure has been adopted: - defining requirements, identification of all activities supported by the geodatabase, analysis of the data flows expected in all supported activities, examining existing data sources and relevant standards (particularly those proposed by the UNGIWG); - development of the data model. The data model has been shaped according to specific needs and demands of the involved user groups within the different interested organizations. The adopted design techniques do not wander off the techniques proposed in literature for general database design, even if it has been necessary, in some steps, to consider the specific features of geographic data; - geodatabase schema generation and implementation of the defined geographic database model as an ESRI ArcSDE Enterprise Geodatabase based on Oracle 10g as DBMS.

Bibliography: pages 134-140.<br>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.

The objective of the research was to study the performance of the least squares collocation (LSC) and the fast Fourier transform (FFT) techniques for gravimetric geoid computation. The Land Levelling Datum (LLD) is the South African vertical datum based on more than 100 years old tide gauge measurements of mean sea level (MSL). The LLD is poorly defined so an alternative is required. The SAGEOID10 (Merry, 2009) hybrid geoid model was computed for the purpose of replacing the existing vertical datum. Two gravimetric geoid models were computed using different techniques for evaluation of the Stokes' integral, such as, LSC and one dimensional fast Fourier transform (1D-FFT) technique. The long wavelength component of the geoid models were computed using the EGM2008 geopotential model truncated at degree 720. The use of fast spectral techniques is required due to an increase of both quality and type of data available for geoid determination. The FFT method is most reliable than the LSC method, since it requires less computational time on large data set than the LSC. A system of linear equations of order equal to the number of data points is generated on the LSC method. The geoid model was computed over the province of Gauteng. It was then compared to the SAGEOID10 hybrid geoid model. The computed geoid models, SiPLSC and SiPFFT geoid model compared to the SAGEOID10 model with standard deviation of 5.6cm. The long wavelength component of the computed geoid model compared to the EGM2008 geopotential geoid model with a standard deviation of 4.2cm.

Population increase in African cities have made it hard to reduce their ecological footprint and attain self-sustainability. This made the United Nations to put forward the seventeen sustainable development goals. Three of these goals centre on provision of clean energy and reduction of reliance on fossil fuels. It is therefore important for cities in Africa to chart a path of attaining sustainability. Consequently, the city of Cape Town is leading the drive for a greener city and self-sustainability in energy. Solar energy, which is regarded as a clean and renewable source of energy, makes it possible to generate electricity by using photovoltaics technology. However, the problem of creating awareness as to the potentials of building-integrated solar photovoltaic system persists. The study is aimed at using remote sensing and Geographic Information Systems (GIS) techniques in creating awareness about the potentials of building rooftops for solar photovoltaics installations in an urban setting. In achieving this, Light Detection and Ranging (LiDAR) data and aerial imagery are sourced from City of Cape Town municipality to serve as the primary data input. Four phases of analysis are involved: (1) extraction of whole building roof outline and its roof planes, using the integration of LiDAR-derived products and aerial imagery, in order to determine the surface area of the roof planes. This is achieved by developing a unique two-in-one, object-based classification rulesets; (2) estimating and validating the global solar radiation incidence on each roof plane, using a LiDAR-derived elevation model in a python script utilizing the GRASS script library; (3) evaluating the solar photovoltaic potential of each roof plane, using inputs from two previous phases to create a solar photovoltaic potential database; and (4) deploying the solution online to create awareness, by utilizing JavaScript and Hypertext Mark-up Language (HTML) to implement a map mashup, which incorporates tile map and table services. This results in a web-based solution, which can be queried to retrieve information about the solar photovoltaic potential of a building roof. From the results generated and the system developed, it becomes possible to remotely and sufficiently evaluate buildings in the city for solar photovoltaic potentials, designs and installations. Thereby reducing reliance on the fossil fuel generated electricity and improving the self-sustainability of the city.

Panoramic images (panoramas) are wide-angle images that provide fields of view of up to 360°. They are acquired with a specialised panoramic camera or by stitching a series of images captured with a conventional digital camera. Panoramas have widely been used to texture 3D models generated from laser scanning, for creating virtual reality tour applications, documenting landscape and cultural heritage sites, advertising real estates and recording crime scenes. The goal of this research was to develop an accurate close-range photogrammetric technique for the semi-automatic extraction of 3D information from spherical panoramas. This was achieved by developing a non-parametric method for the removal of distortions from images acquired from fisheye lenses as well as an algorithm, here referred to as the Minimum Ray Distance (MRD), for the fully automated approximate relative orientation of spherical panoramic images. The bundle adjustment algorithm was then applied to refine the orientation parameters of the panoramas; thus enabling accurate 3D point measurement. Finally, epipolar geometry theory was applied to the oriented panoramas to guide the interactive extraction of additional conjugate points. The MRD algorithm has been extended to laser scanning technology for the first approximations of laser scan setup positions and scan orientation prior to a leastsquares based registration. The determination of approximate scanner orientation and position parameters were accomplished using panoramic intensity images derived from full dome laser scans. Thus, a technique for the semi-automatic extraction of 3D measurements from panoramic images has been developed in this research. The technique is most appropriate for applications which do not require dense point clouds and in situations with limited access to funds or as a quick field method to document many features in a short time. This is because a single image orientation is required for several overlapping images as compared to the normal stereo or multi-image photogrammetric approach. It is not suggested that 3D reconstruction from spherical panoramic images should replace traditional close-range photogrammetry or laser scanning; rather, that the user of panoramic images will be offered supplementary information to the conventional and modern cultural heritage documentation approaches.

Bibliography: leaves 91-97.<br>The quest for sustenance inevitably forces mankind to exploit natural resources found within their environs. In many cases, the exploitation results in massive environmental degradation that disrupts the ecosystem and causes loss of bio-diversity. There is generally a lack of information systems to monitor and provide quantitative information on the state of the affected environment. Decision-makers usually fail to make informed decisions with regard to conservation strategies. The need to provide decision-makers with quantitative environmental information formed the basis of this thesis. An integrated environmental information system (EIS) database was developed according to the Software Development Methodology for three of the identified environmental sectors. This involved detailed user needs assessment to identify the information requirements (both spatial and textual) for each sector. The results were used to design separate data models that were later merged to create an integrated data model for the database application. A fisheries application prototype was developed to implement the proposed database design. The prototype has three major components. The Geographic Information System (GIS) handles the spatial data such as rivers, settlements, roads, and lakes. A relational database management system (RDBMS) was used to store and maintain the non-spatial data such as fisherman ' s personal details and fish catch data. Customized graphical user interfaces were designed to handle the data visualization and restricted access to the GIS and RDBMS environments.

Includes bibliographical references.<br>Personal privacy issues are relevant to the GIS community. The distribution and dissemination of personal data is greatly facilitated through GIS tools. The use of these tools has been expanded from traditionally geographical operations to applications in geodemographics, and it is particularly in geodemographics where the protection of privacy becomes an issue. This thesis examines existing privacy protection guidelines put forward by international commercial and governmental sectors; the current international position with regards to the protection of privacy is reviewed, and South African legislation pertaining to these issues is explored. On this basis, a set of privacy protection guidelines is developed which can assist GIS managers in South Africa in ensuring that data collection and management do not infringe on personal privacy.

This thesis introduces an alternative formulation for line photogrammetry. The aim was to develop and test a method of computing the position and orientation of a straight line in space using two or more oriented images of that line. The algorithm presented is intended for object reconstruction and is motivated by the need to reconstruct man-made objects in urban areas, such as buildings and the industrial inspection arena. The method aims to obtain a best-fit line through a "pencil of planes". The reconstructed 3D line is defined by two points as opposed to the conventional representation, which uses a point and a direction vector. The approach to this problem involves the calculation of a projection plane for each image containing the perspective centre and two transformed line-point observations in the image. A least squares adjustment involves fitting a straight line as near as possible to the projection planes from all images simultaneously. The adjusted line is referred to as a best-fitting line through a "pencil of planes" (POP). In this project, a mathematical model was formulated for the application of this concept. This algorithm was coded and tested on two cases. A set of scanned aerial images of a residential area with a scale of 1: 5000 provided the primary test case. Lines delineating three roofs visible in the aerial images were reconstructed using the POP method and compared with ground truth data. The lines reconstructed using the POP method were compared to those reconstructed using an existing method of line photogrammetry, proposed by Mulawa (1988). The second test was based on a set of close-range images captured using a small-format digital camera. Lines delineating the bars of a metal frame generally used as a precise control field for camera calibration, were reconstructed. In both test cases, X² tests were applied, and the standard deviations calculated. In the aerial case, standard deviations obtained were generally in the region of about 5cm. The ground resolution of the images was 7.Scm. In the close-range case the ground resolution was approximately 1.3mm, and the standard deviations obtained were generally of the order of 0.7mm. Of the lines computed, 84% of the adjustments passed the X² test. The results obtained confirmed that the POP algorithm is a practicable means of adjusting observations to obtain best-fitting 3D lines using observations made in a set of oriented images.