DEMs from IGN#
IGN provides several DEM datasets at different resolutions (IGN datastore).
BD ALTI 25m#
Description#
These data are available on cartes.gouv.fr in the ASCII format, as square tiles of 25 km × 25 km, under the CRS epsg:2154.
GEOP4TH workflows#
Once downloaded, these ASCII tiles can be standardized (one single file, embedded CRS, geospatial format such as GeoTIFF…) by using the function standardize_bdalti.
Standardized DEM data can then be used in application workflows such as cwatm_dem, which reprojects and clips data as demanded, and generates maps of flow directions and elevation standard deviation.