Maps digitally calibrated based on elevation reliefs containing information related to the altitude of the ground. With a relief map loaded you will be able to display your maps in 3D mode. TwoNav offers free 3D reliefs from all around the world.
Map created by Bernard Perrot (rando.tybern.fr). Get elevation models with even higher definition at https://rando.tybern.fr/telechargements/MNT/