The latest edition of the "International Specifications for Orienteering Maps" (ISOM2000) contains a section for Ski-O maps for the first time. Ski-O maps show the prepared trail network in green, superimposed on the underlying roads and tracks. There are also symbols to represent roads and tracks that do not have ski-trails on them.
Generally Ski-O maps use the same symbols as foot-orienteering, although the off-track details are simplified as they are not relevant. Open land is shown as yellow and forest as light green. The scale for Ski-O is 1:10,000 or 1:15,000, and the contour interval 2.5, 5 or 10m. But note that this is "early days" for Ski-O in NZ, and you will get maps which don't conform to the standard. Don't let it stop you enjoying your skiing!!
There are three categories of trail. Those wider than 2m are shown with a thick green line. Between 1 and 2m the symbol is a dashed green line, and under 1m a dotted green line. If there is a path under the snow the symbol is superimposed on top of the black line, if there is a road the symbol is to one side.
Roads that are cleared of snow but still skiable are shown with the
normal black road symbol. Roads and paths covered with snow
which do not have a trail following them have green cross
lines superimposed. Prepared slalom slopes where you can travel in
any direction are shown with a green cross-hatch.