The dedicated contour-vector conversion effort associated with the move from map sheets to a national topographic database.
Demand for digital elevation and topographic geometry drove a national contour-capture programme during the 1990s. A 1999 technical account describes the use of Mapsetter and VTRAK tools to convert topographic contour sources while national detailed topographic database coverage was still being assembled.
The work converted and checked contours drawn on earlier topographic compilation sheets. The resulting vector terrain representation retained the accuracy limits of its mapping sources and preceded the later Topo50 data-delivery products.