THE IGN (FRANCE) TOPOGRAPHIC DATABASE

The French topographic database is a three dimensional database whose content is very near to that of the IGN 1:25 000 scale maps. It has a metric accuracy and is designed to have three aims (maps at scales of 1:25 000 and 1:50 000 and the topographic part of the cadastral map at 1:5000 scale, providing located structured data). The structure, including topology information, is described. The process of data capture is based on photogrammetry and field completion. Experiments concerned with revision are being made in order to define the methodology precisely.