I am using QGIS 2.18.15. I got some trouble to add an asc-file as a raster layer into QGIS. I tried to add the raster layer the normal way via the tool bar bottom. It did not work. (“The file source is not supported”)
Then I tried to convert the data via Raster: Conversion: Translate (convert format) menu option as it is suggested at StackExchange (Manipulate .asc files in qgis). It did no work ether. Here is the same problem “not recognized as a supported file format.”
The data I would like to add is from the following link. ftp://ftp-cdc.dwd.de/pub/CDC/grids_germany/multi_annual/solar/
It does not matter which data package I downloaded neither of them worked out.