The eTOD digital terrain model (DTM) is a homogeneous and regular point grid that models the height of the ground level for Belgian territory and the height of the sea level in the maritime zone. The primary source is the NGI DTM 5m, which is itself compiled based on the most recent altimetry data of the three Belgian regions and is periodically updated per map sheet at a scale of 1:50,000 using recent stereoscopic aerial images. Where available, updates from the notification platform for aviation obstacles and terrain changes are also integrated. For this DTM, the resolution (1 arcsecond) and the coordinate reference system (WGS84 + EGM2008) are used as defined in the eTOD specifications.

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.

This dataset contains the orthophoto mosaics that were created following the floods of July 2021 in the valleys of the Vesdre, the Meuse and the Demer. Orthophotos are aerial photographs that have been geometrically corrected (orthorectified) to eliminate distortions caused by terrain relief, lens distortion, and camera tilt. Unlike raw aerial imagery, orthophotos have a uniform scale and accurate geometry, making them suitable for cartography, measurements, and visual analysis. This specific dataset includes orthophotos based on aerial photographs acquired in July 2021 by Hansa Luftbild, commissioned by the National Geographic Institute (NGI), following the floods in the zones of the Vesdre, a part of the Meuse downstream of Liège and the Demer. The resulting orthophoto mosaics are georeferenced in the Lambert 2008 coordinate system. All orthophotos are in colour (RGB). The ground resolution (GSD) is 6.5 cm (4 cm above the Hoëgne). The spatial coverage of this dataset is limited to the affected zones. The data can be visualized via the corresponding web service (WMS). The data is available on request via https://ngi.be/aanbod/kaarten-en-fotos/luchtfotos-orthofotos/.

DSM 1m is a homogeneous and regular point grid indicating the height of the Earth’s surface level in order to model its landscape. DSM 1m is achieved by interpolating in Lambert 2008 source data in Lambert 72 and at a 1m-resolution from the Flemish and Brussels Regions, and by adding Lambert 2008 data at 1m-resolution from the Walloon Region.

The DTM is a homogeneous and regular point grid indicating the height of the ground level in order to model its surface. The DTM 1m is achieved by interpolating in Lambert 2008 source data in Lambert 72 and at a 1m-resolution from the Flemish and Brussels regions, and by adding Lambert 2008 data at 1m-resolution from the Walloon Region. The DTM 5m has an additional source, namely drawn structure lines and points adapted during systematic and continuous update by photogrammetric surveys. The DTM 20m is obtained by resampling of the DTM 1m.

This dataset shows a digital surface model. It is a homogeneous and regular points grid which indicates the height above the surface of the earth, either the soil or any other permanent and visible element in the landscape (vegetation, construction,…). These data represent the situation of the landscape resulting from the July 2021 floods in het areas of the Vesdre, of part of the Meuse downstream from Liège and of the Demer.

The hillshades are presented as a regular homogeneous grid of points indicating the grey level value resulting from their orientation with respect to the chosen fictitious light source. The 1m hillshade is the view obtained by hillshading of the 1m DTM. The 5m and 20m hillshades are the views obtained by hillshading of the 5m and 20m DTM.

MapIndex is a regular grid of rectangular or square cells coded with alphanumeric characters. It has been defined for the Belgian territory and allows geolacating several events. The present version is a beta (v2)version which is submitted to the emergency services. It will evolve to a standard cartographic grid.