Dear fellow mappers
During this winter, I have taken lonvias excellent route map [1] framework [2] and extended it to render skiing slopes, sledding pistes and snowshoe trails. If you want to have a look go to http://slopemap.osmd.ch, and look for your favourite winter sports area.
The map displays ways and relations tagged with piste:type, and for downhill skiing requires the tag piste:difficulty.
A short remark for the tagging: pistes are usually mapped as ways. I have seen quite a few examples where the name of the piste was mapped as the name tag, or the number as ref. To avoid ambiguity, use the piste:ref tag for the number/letter and the piste:name tag for the name.
Have a nice weekend Michael
[1] http://waymarkedtrails.org [2] https://github.com/lonvia/waymarked-trails-site [3] http://slopemap.osmd.ch