GAMBIA

Gambia is a linear West African state extending 150 miles inland along the Gambia river. The Department of Lands and Survey (GDLS) in Banjul is responsible for surveying and mapping and has published topographic and cadastral maps with support from British, German and American aid in the years since World War II.

The British Directorate of Colonial Surveys (later Directorate of Overseas Surveys (DOS) and now Ordnance Survey International (OSI)) initiated modern mapping of the country with an uncontoured 30-sheet map. This was superseded by a 20-sheet photomap also on the Transverse Mercator projection, Clarke 1880 ellipsoid (Series DOS 415P), compiled from 1972 aerial coverage and published between 1975 and 1977 with hachures and spot heights indicating relief. Since the 1970s photomaps have been extensively used to enable rapid creation of a modern map base of the largely flat flood plain topography. Other DOS mapping at this date included a 1:25,000 scale eight-sheet topographic map of the Kombo Peninsula with 10 m contours. This series was derived in part from photogrammetric plotting and in part from a 1:10,000 scale coastal strip map, published with a 5 m contour interval. Larger scale programs of cadastral maps were updated using aerial coverage in the DOS programmes and cover all the main settlements in the country at 1:1,250, 1:2,500 and 1:5,000 scales. These sheets are available from GDLS as diazo prints. DOS also published a two-sheet 1:250,000 scale map of Gambia. A map of electoral districts at this scale is also published.

In the 1980s a new basic scale map was surveyed for the whole country in 526 1:10,000 scale sheets. This diazo land use photomap was produced by the German Agency for Technical Cooperation, in conjunction with other German agencies. Urban growth centers were also mapped in this program and published as full topographic editions in 44 1:10,000 scale sheets. Other mapping in the late 1980s included the publication of a number of 20-sheet 1:50,000 themes and four-sheet 1:125,000 scale resources series. Land use, forest cover, agriculture and rangelands were compiled.

Since 1992 Gambia has used American, and German funding to establish an integrated environmental action plan, building upon these resources maps. It has been proposed to establish a decentralized environmental information system under the aegis of the new National Environment Centre, with existing 1:50,000 scale mapping captured and held in a structured digital database. New 1:25,000 scale colour aerial coverage was flown in 1993, and new black and white coverage a year later. It is intended to use the information system to derive 1:125,000 scale datasets for environmental management and to extend digital mapping to cadastral systems. A number of land use scales have already been compiled, including new 1:30,000 scale coverage of Banjul.

Soviet military mapping of Gambia is available at the following scales: 1:1,000,000 (1 sheet, complete coverage, published in 1986); 1:500,000 (2 sheets, complete coverage, published in 1985) and 1:200,000 (8 sheets, complete coverage, published 1985-1986). These products are available in paper, digital raster and digital vector GIS from East View Geospatial.