4. Electronic Theses and Dissertations (ETDs) - Faculties submissions

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Browsing 4. Electronic Theses and Dissertations (ETDs) - Faculties submissions by Author "Adam, Elhadi"

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    The Assessment of the Current Geographical Information System (GIS) initiatives in the public enterprises of Swaziland
    (University of the Witwatersrand, Johannesburg, 2022) Khumalo, Malungisa Blessing; Adam, Elhadi
    There is a growing use of geographic information systems (GIS) within the public sector in many countries. GIS require considerable financial resources and investment in information and communication technology (ICT) and human resources, which are primarily financed by public funds. The growth in adoption is partly influenced by the promising potential of GIS that has been widely discussed in the literature on GIS. The usefulness and application of GIS in aiding decision making and in public policy formulation and implementation have also been widely discussed in the literature on GIS. To examine the effectiveness of GIS in public policy, one has to develop a mechanism for measuring the success achieved by the implementation of GIS in decision making. However, the methodologies for the evaluation of the use of GIS in the public sector are mainly lacking. The aims of this research were to evaluate the effective use of GIS in the public sector in Swaziland. Three organisations were selected, namely the Swaziland Posts and Telecommunications (SPTC), Swaziland Water Services Corporation (SWSC) and Swaziland National Housing Board (SNHB). Like in most developing countries, the lack of GIS evaluation to improve implementation is a challenge for these organisations. The current GIS applications at SPTC, SWSC and SNHB were evaluated using maturity, value and GIS product assessments. Four methods of analysis were used for data analysis: GIS maturity calculation; relative frequency of maturity calculation; gap analysis; and GIS value assessment. The results found that the SPTC, SWSC and SNHB were all in the exploitation stage of maturity. The overall relative frequency of maturity in the dimensions is the following: 35% of indicators are in the exploration stage; 56% are in the exploitation stage; and 9% are in the enterprise stage. The gap analysis shows that the organisations are in the exploitation stage of maturity. Cost prevention, coordination, employee satisfaction, better data management, time saving and better quality of information were regarded as the main ways in which GIS add value to organisations. The GIS product assessment results show that the overall compliance rate with the cartographic standards is 57.09%.
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    Use of Multispectral Satellite Imagery to Monitor the Decant Pond of Tailings Dams
    (University of the Witwatersrand, Johannesburg, 2023-08) O’Donovan, Christopher Galen; Adam, Elhadi; Torres-Cruz, Alberto
    Tailings dam failures, such as the Jagersfontein failure in the Free State province and the Fundão and Feijão failures in Brazil, have brought into question the ability of the mining industry to operate safely, threatening its social license. To improve the safety of tailings dams, leading indicators of dam safety should be monitored. The location and historical behaviour of the tailings decant pond provides insight into several such leading indicators and can be used as a proxy to flag potential construction issues. This work investigates the use of public multispectral data collected by the Sentinel-2 satellite mission to monitor the supernatant tailings dam decant pond. This is achieved by leveraging the cloud-based Google Earth Engine platform and open-source GIS tools. Sentinel-2 acquires visible and near infrared spectrum data with a spatial resolution of 10 m and a revisit time of 5 days. Pond data is obtained by visual assessment and automated thresholding of Sentinel-2 imagery. Thresholds of near-infrared (NIR) reflectance and the normalised difference water index (NDWI) obtained by a least square error analysis are investigated. Implementation of the method at three South African tailings dams, constituting four decant ponds, illustrates the capabilities and limitations of Sentinel-2 imagery. High spatial resolution (<5 m) multispectral satellite imagery and natural colour aerial orthophotos (<0.25 m) serve as reference data. Visually assessed Sentinel-2 pond data presented a bias towards slight over estimation of the pond area compared to reference data. Other leading indicators did not show systematic bias across all sites. In general, the deviation between Sentinel-2 and the reference measurements was high, indicating that Sentinel-2 imagery should be used with caution for measurements critical to dam safety. Site-specific thresholds of NIR and NDWI indicated that automated thresholding of the NDWI is superior to NIR reflectance alone. It is shown that Sentinel-2 timeseries imagery can be used in tailings dam monitoring to supplement existing construction surveillance frameworks and provide historical pond data in the absence of such information.