The osm ++ maps prepared by TYDAC (WMTS and WMS services) are based on the one hand on OpenStreetMap (OSM), supplemented by (hence ++):
Data is processed at least quarterly and roughly covers the alpine ridge. In addition to osm europe we supplement:
Tiles of the WMTS are processed down to a scale of approx. 1: 2'500. Data volume is 420GB.
The data is at least updated quarterly for almost all of Europe (except North Scandinavia and far east). Some key figures:
Tiles of the WMTS are processed down to a scale of approx. 1: 5,000. Data volume is 685GB.
Example (Mercator Projection, slightly different zoom levals as in osm alps):