ABSTRACT
The natural form of the DEM is raster (a regular grid of altitudes), either acquired by correlation or by laser scanning. But, given their extremely heterogeneous nature and the presence of discontinuities, this format is neither adapted to their storage nor to their manipulation. The construction of a TIN (for triangulated irregular network) presents the two favourable features to reduce greatly the volume of data (a reduction of around 90 per cent for an urban DEM) and to be more effective for all applications of visualizations [1] (Figure 3.5.1.5). Besides, this construction is a first raw data interpretation that may facilitate the analysis of the scene [2].
