Browsing by Author "Martin, C G C"

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    Cartographic GIS standards adopted by the Department of Water Affairs and Forestry : a case study
    (1996) De Klerk, Jeanne Louise; Martin, C G C
    The Department of Water Affairs and Forestry (DWAF) acquired a Geographic Information System (GIS) in 1987. The purpose of acquiring such a system was to aid the department in implementing their water resource management strategy of that time. On acquiring this system it was well recognised that the GIS would need to communicate geo-referenced information, generated by analysis and modelling to decision makers by means of graphic representations or maps (Olivier et al., 1990: 14 73). Towards the end of 1990 it became apparent that the department needed to standardise cartographic output of this system. Maps on the same theme, which were produced at different sites were not comparable and graphic communication was not effective. A consultant was appointed, who, in conjunction with the departmental digital cartographer, established criteria and standards which were flexible enough to accommodate mapping on a wide variety of themes. These standards were implemented, to a limited extent in July 1994. Standards were set for map encoding, map content and map composition. This report investigates how effective these standards have been. The effectiveness of these standards have been measured in terms of the five recognised cartographic design principles that have been identified by Robinson et al. (1984), Wood (1992) and Dent (1990). These include the clarity and legibility of maps, the distinction between figure and ground, the hierarchical organisation of mapped information, the visual contrast of marks on maps and the visual balance or layout of the finished map. A sample of maps made after the implementation of cartographic standards at the department was compared to a sample of comparable maps made prior to the implementation of these standards. In a large organisation like the department the success of such standards do not depend on the standards alone but also on their implementation. Implementation related problems were identified by comparing standardised maps with the standards. The outcome of the investigation proved that the effectiveness of graphic communication had indeed improved albeit to a varying degree. In most cases the standards were adequate and the main problems actually lay with their implementation. Recommendations on the implementation and the few aspects of the standards that require amendment have been included in this report.
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    The development of a Geographic information system for environmental monitoring on the Cape Peninsula, and an assessment of the use of spot imagery for vegetation mapping
    (1991) Webster, Michael S; Moll, EJ; Martin, C G C
    This thesis concerns the establishment of a Geographic Information System for the Cape Peninsula and the use of SPOT satellite imagery to map land cover classes. The former is seen as a necessary tool to promote judicious conservation management decisions for the fragile "Fynbos" ecosystem, and the latter as a convenient means of acquiring up-to-date information concerning the environment, and to monitor change.
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    The implementation of the International Hydrographic Organisation's Worldwide Electronic Navigational Chart Data Base for Electronic Chart Display and Information Systems : the implications to sub-Saharan Africa
    (1996) Osei, Samuel; Martin, C G C
    This report gives suggestions to sub-Saharan Africa regarding the implementation of the International Hydrographic Organisation's (IHO) Worldwide Electronic Navigational Chart Data Base (WEND) for Electronic Chart Display and Information _systems (ECDIS). The IHO, recognising the need to supply up-to-date navigational information to mariners at sea, proposes the establishment of a worldwide network of navigational information. This proposal is aimed at addressing the information needs of international shipping. However, it does not restrict any hydrographic office from developing its own data base for national shipping. ECDIS is one new technology that will improve safety at sea. It integrates the Electronic Navigational Chart (ENC) and other navigational information. Unlike the paper chart, ECDIS will select and display information that is needed at any chosen moment thereby removing clutter from the display. The mariner will only see the information that is relevant for his immediate decision-making. ECDIS is versatile, complex and a potentially important aid to navigation decision-making. It enables mariners to navigate under conditions of poor visibility and through narrow and poorly-marked channels. It has the power to process data from a variety of sources and to detect and graphically show relationships between the data. Since history requires us to look at the past and the present to be able to project into the future, the report begins by giving the background to electronic charts. The report examines the traditional paper chart and the present method of updating the chart. It looks at the information contained in the Notices to Mariners, Radio Navigational Warnings and Global Maritime Distress and Safety Systems. The responsibilities and obligations of the various professional disciplines involved in updating the paper chart are also discussed. The limitations of the paper chart are commented upon and the need for a new technology is emphasized. The procedure for updating the electronic chart is also discussed. The terms "paper chart" and "traditional paper chart" are used interchangeably and mean the same thing in this report. The second chapter examines the requirements of ECDIS. It discusses the user requirements and the minimum system configuration. Operational and performance requirements are also examined. Chapter Three discusses the Worldwide Electronic Navigational Chart Data Base (WEND). It gives a brief background to WEND and discusses the conceptual model of the organisation of WEND on regional bases. It examines a paper presented by Australia in relation to a single state WEND proposed by Norway. Since the whole process of networking the navigational information depends on technology, an in-depth treatment of the subject is carried out in Chapter Four. Issues discussed include networking and distributed system, standards and protocols in telecommunications. The design consideration for the infrastructure for a Regional Electronic Navigational Chart Coordinating Centre (RECC) is dealt with in Chapter Five. Financial and institutional issues are discussed. Technical and non-technical security measure are commented upon. Chapter Six deals with the infrastructure design for a RECC. It examines the infrastructure components, system operation and maintenance and manpower. Strategies for implementing RECC in the sub-Saharan Africa are discussed in Chapter Seven. Network development, data and system security measures are commented upon. Chapter Eight looks at the legal implications of ECDIS and WEND. It examines the elements of the legal regime and speculates on the possible changes that could be brought about as a result of the changing technology. Chapter Nine concludes the report with recommendations on a regional WEND centre.