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Environmental Science

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Browsing Environmental Science by Subject "Aerial photogrammetry."

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    Analyzing an orthophoto mapping system using system analysis, SWOT and client satisfaction survey : a case study of the Chief Directorate of Surveys and Mapping, Republic of South Africa
    (2010) Mnyengeza, Mnqweno.; Chimhamhiwa, Dorman.
    An orthophoto map is made from a combination of different geospatial datasets such as relief, imagery, powerlines and annotation. These data sets are usually generated by different divisions within national mapping agencies. Often, when an orthophoto mapping project is to be undertaken, other functions within and outside the system, are actuated. Examples of such functions include; photogrammetric scanning, digital elevation capturing, aerial triangulation, ancillary data and imagery acquisition and map compilation. This research is underpinned by the hypothesis that different components that supply data required for generating orthophoto maps do not work as a coherent whole. This behaviour impacts negatively on the production of orthophoto maps as well as the quality of the end product and can have spill over effects on service delivery. In this research, systems analysis, client satisfaction survey and SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis are used as a collective set of tools to analyze an orthophoto mapping system (OMS) in order to mitigate this unwanted behaviour. The case of orthophoto map production at the Chief Directorate of Surveys and Mapping (CDSM) in South Africa is used. First, systems analysis, which uses the Data Flow Diagram (DFD) technique, is employed to depict the system‘s data stores, processes and data flows. This approach helps to show how the current system works thereby assisting to pin point areas that require improvement. After presenting the system ‘s processes, data stores and data flows, a client satisfaction survey, built on the criteria of; accuracy, completeness, correctness and accessibility of geospatial datasets, is conducted on one of the data stores – the Topographical Information System (TIS) database. Finally, a SWOT analysis is then done on the whole OMS to evaluate the internal and external environment under which the current system operates in. Gaps are identified and recommendations suggested. Although in this case, the recommendations are built based on the CDSM case study, it is believed they can benefit other OMS’s in similar operating conditions elsewhere.