St Helena, together with Ascension Island and Tristan da Cunha, form a British Dependency. The island has been mapped by the former Directorate of Overseas Surveys (now Ordnance Survey International (OSI)) of the British Government. An early triangulation of the island took place in 1903 and was used as a basis for military survey, but a new triangulation was observed by the DOS in 1971 using EDM methods to provide control for a 1:10,000 scale series compiled from photography flown by helicopter in 1970. This 1:10,000 scale map (DOS 260) was published in 1974 in six sheets. In 1990, new mapping was published by OSI. This comprised a second edition of (DOS 260) also in six sheets, reconstructed from 1989 RAF air photography. The data was digitally captured during plotting. The map is printed in two colors and has 10 m interval contours, including bathymetry on Sheet 2. The projection is Transverse Mercator, International ellipsoid. Derived maps at scales of 1:50,000 and 1:25,000 were published in the same year. The 1:25,000 scale map is adapted for tourists, with a descriptive text and places of interest named in red. The 1:50,000 map is a simple outline map in black with no contours. There is also an A4 sized country map with hill shading.
A new series of 1:2,500 scale sheets was published in 1992 (OSD 060) with 5 m contours. The 20 sheets cover Jamestown and Longwood and were compiled from 1:10,000 digital data, and enlarged 1:10,000 mapping, and are printed as dye-lines.
The Legal and Lands Department is locally responsible for mapping on Saint Helena.
In 1982, a geomorphological map at 1:10,000 scale of Saint Helena was compiled by an expedition from the Department of Geography, University College London (UCL).
The original 1:10,000 scale series was used as a base map for a forestry and development project carried out by the Land Resources Development Center (LRDC) (now Natural Resources Institute (NRI)) and published as Land resource report 2. The forestry maps accompanying the report are (DOS 3025). In 1980, a new Land Resource Study of Saint Helena (LRS 32) was published by LRDC. This includes five 1:25,000 scale maps of geology, land units, soil, vegetation and re-afforestation, as well as a three-sheet land use series at 1:10,000 scale. A new 1:25,000 scale land use map compiled by the Agriculture and Forestry Department of St Helena was published in color by OSI in 1990.
Exploring Saint Helena: a walker’s guide, has been published by Anthony Nelson.