Ski Orienteering is a sport where competitors navigate on skis through diverse terrain and visit, in sequence, different points on a map. The competitor with the quickest time of completion is the winner.

Ski orienteering is a form of orienteering performed on cross-country skis. Participants use standard orienteering maps with special green overprinting of trails and tracks to indicate their navigability in snow; other symbols indicate whether any roads are snow-covered or clear. Standard cross-country ski equipment is used, along with a map holder attached to the chest. The World Ski Orienteering Championships is the official event to award the titles of World Champions in Ski Orienteering. The World Championships is organized every odd year. The program includes Sprint, Middle and Long Distance competitions, and a Relay for both men and women. The World Cup is the official series of events to find the world's best ski orienteering over a season.

The goal of ski orienteering is to use a map and compass to traverse a pre-determined course in the shortest amount of time.

The rules for ski orienteering are competitors must determine, along an accessible course no competitor may leave, which of various controls in a small area is the one indicated on the map.

Compass
Cross-country Skis
Map
Map Holder

Ski orienteering requires basic navigation skills in order to read the map correctly and be able to navigate to each location. It also requires some skill at cross-country skiing.

http://en.wikipedia.org/wiki/Orienteering#Ski_orienteering