Rendering OSM data

Sign-posted slopes are ways with the piste:type tags. To be recognized as a slope, the following tags need to be present for ways:

piste:type = downhill|nordic|sled|hike|sleigh

For relations, the following tags need to be present:

type = route|superroute
route = ski|piste
piste:type = downhill|nordic|sled|hike|sleigh

The classification of ski (downhill) slopes is determined from the piste:difficulty tag, and used for the colour in the rendering.

The label for ski (downhill) routes is "guessed" from the tags in the following order:

  1. If a piste:ref tag exists, make a text label with the piste:ref tag.
  2. If a piste:name tag exists, derive a reference from that, first by using only upper-case letters and failing that by using the first letters of the name.
  3. If a ref tag exists, make a text label with the ref tag.
  4. If it is a relation and a name tag exists, derive a reference from that, first by using only upper-case letters and failing that by using the first letters of the name.
  5. Give up.

Nordic slopes are marked with a sign just showing their colour, if a colour tag is present.