The contour lines are the set of lines connecting all points at the same elevation in a model used to represent the relief on a large scale.

The INSPIRE contour lines used for a cartographic representation of the relief at scale 1:50000, a product of the National Geographic Institute in Belgium. The dataset features are in accordance with the INSPIRE specifications.

The digital terrain model (DTM) is a homogeneous and regular point grid indicating the elevation of the ground level in order to make a model of its surface. The 1m DTM is obtained by interpolation in Lambert 2008 of the raw height data regrouping the source data, in Lambert 72 and at 1m resolution, of the Flemish and Walloon regions. The 5m DTM has as an additional source structure lines and adapted points, during the systematic and continuous updating by photogrammetric surveys. The 20m DTM, available for free download, is obtained by resampling the 1m DTM.