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.
Copyright © 2014 East View Geospatial, Inc.