A HIGH resolution digital image covering the whole of Britain will be available within three years following a formal agreement between three specialist mapping firms and Ordnance Survey.
GeoInformation Group, Getmapping and UK Perspectives are to work together to produce a seamless photographic mosaic generated from an estimated 300,000 separate digital photographs.
The images will have a ground resolution of 250mm and will be orthorectified to combat foreshortening, making them geometrically identical to conventional maps.
This process will allow accurate measurements of ground distance to be taken from the images, as from maps, and means the images can be used in automated mapping software along with other digital cartographic data.
The imagery will form a layer in OS MasterMap, Ordnance Survey's new digital map data and online service (NCE 6 December 2001), allowing users to overlay photography and mapping of an identical area.
Individual images will be updated as part of an ongoing programme of revision.
INFOPLUS www. ordsvy. gov. uk