Cartographic Process

In 1936 a landmark decision was made to map South Africa at 1:50 000 scale using aerial photography and by 1973 full coverage (1613 maps) was achieved. The 1:50 000 National Map Series is the largest scale providing complete coverage of South Africa.

In 1997 the traditional manual cartographic methods (fairdrawing) were replaced by computer assisted map production systems and cartographers were trained to use computers to produce maps.

A centralized dedicated Geographical Information Data base was created to provide data in vector format. The Data Base is maintained and updated continuously from the latest available aerial photography and this data is used for the revision of 1:50 000 topographical maps. The Spatial Data from the GIS data base is imported into the cartographic environment where the data is structured according to the 1:50 000 map specifications, and cartographic rules are applied.

The map data is created as a Postscript file and on completion this file is then converted to a Geo-Referenced Tiff File and archived. The Tiff file is used as the final output file to a printing device, either lithographic or inkjet printers.

High quality inkjet printers have enabled the National Geo-spatial Information to print most of the maps in house except where large quantities are required when the lithographic process is used.

The 1:50 000 maps are made available to the public as hardcopy (paper) prints or as Geo-referenced Tiff files in digital format.

The 1:50 000 National Map series forms the basis on which the 1:250 000, 1:500 000 and the 1:1 000 000 are derived. Generalisation techniques are used to capture levels of detail required at the smaller scales, taking cognisance of the intended use and purpose of the map.

The 1: 10 000 Orthophoto map series uses rectified digital aerial photography as a background to the map .Cartographic elements that cannot be derived from the photographic background (for example contours, names and symbols) are added . The maps are produced using computer assisted map production methods and the final output files are archived as Geo-referenced Tiff files.

The 1:10 000 Orthophoto maps are available as hardcopy (paper prints) or as Geo-referenced Tiff files in digital format.

The Chief Directorate National Geo-spatial Information is responsible for the production and distribution of Aeronautical Charts on behalf of the South African Civil Aviation Authority. The Aeronautical Charts are produced at a scale of 1:1 000 000 and 1:500 000 and are compliant with the International Civil Aviation Organization's standards and specifications. These charts depict Airspace geometries as well as Aerodrome information and are used by pilots using Instrument Flying Rules (IFR) and Visual Flying Rules (VFR). Aeronautical information is supplied to the Cartographic Division by the Civil Aviation Authority and the maps are made using computer assisted map production methods. The charts are available in hardcopy (paper) prints from our Map Sales Division as well as approved vendors.

The introduction of Computer Assisted Map Production has enabled the Cartographic Division to provide a wide variety of map products and services. In 2009 a milestone was achieved when in partnership with the Pioneer Printing Works, the first Braille Atlas in South Africa was produced and printed.

Computerised mapping techniques and GIS have both revolutionized cartography and reduced the need for as many cartographers as there were when manual methods were used. The introduction of new systems has meant that traditional methods have to be supplemented with new skills.