See Also...International Specification for Orienteering Maps ISOM Index Symbols Index previous next
revision 01/00
4.1 Land forms
The shape of land is shown by means of very detailed contours, aided by the special symbols for small knolls, depressions, etc. This is complemented in black by the symbols for rock and cliffs. Orienteering terrain is normally best represented with a 5m contour interval. (1990- now moved to a new section 3.2 Contour Interval) An interval of 2.5m may be necessary in certain types of terrain. It is not permissible to use different intervals on the same map.
Excessive use of form lines should be avoided as this will complicate the map and give a wrong impression of height differences. If the representation of an area needs a large number of form lines, a smaller contour interval provides a more legible alternative.
The relative height difference between neighbouring features must be represented on the map as accurately as possible. Absolute height accuracy is of less importance. It is permissible to alter the height of a contour slightly if this will improve the representation of a feature. This deviation should not normally exceed 25% of the contour interval and attention must be paid to neighbouring features.
Contour
Index contour
Form line
Slope line
Contour value
Earth bank
Earth wall
Small earth wall
Erosion gully
Small erosion gully
Knoll
Small knoll
Elongated knoll
Depression
Small depression
Pit
Broken ground
Special landform feature
Platform (BOF not ISOM)
Spot height
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ISOM Cover
Symbols index
Map Index
Land forms
Rock and boulders
Water and marsh
Vegetation
Man-made features
Technical symbols & Map contents
Overprinting symbols
Symbols for other disciplines
OCAD characters
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