Reference: International Specification for Orienteering Maps, IOF 2000, Section 7, Map Specification for Trail Orienteering.
Maps for international trail orienteering are based on foot orienteering mapping specifications and are usually amended versions of sections of foot orienteering maps.
The fact that the competitors in trail orienteering are forbidden to leave the tracks, paths and marked routes (referred to as 'trails') has a number of consequences for trail orienteering mapping.
The competition area is that adjacent to the trails, generally within 50m. Concentrating on this greatly reduced area, compared with foot orienteering, requires a much more detailed terrain representation and consequently an enlarged map scale:
Map scale for international trail orienteering is 1:5000
The enlarged scale demands increased symbol size but not pro rata:
Symbol dimensions to be 100% greater than for 1:15000 foot-O maps
The map must fairly represent the terrain as seen from the trails and non-visible features may be omitted, if their inclusion would otherwise distort the map.
The concept of runnability cannot apply in trail orienteering and is replaced by those of appearance and visibility.
The precision with which a control flag is positioned in trail orienteering may be to 1m or even better. At a map scale of 1:5000 this is centring the control circle to 0.2mm or better. This means that the control circles are produced as an edition of the map and not overprinted.
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