ISOM front page  Map style index  Text index  Land forms index  Rock and boulders index  Water and marsh index  Vegetation index  Man-made features index  Overprinting and technical symbols index  OCAD symbols index  email to author

Forest: difficult to run 408

See Also...409  406   ISOM Index  Vegetation index    previous   next

This page contains content from ISOM2000   This page contains content from Ashby Mapping      revision 05/00


408 Forest: difficult to run

An area with dense trees or thicket (low visibility) which reduce running to ca. 20 - 60% of normal speed.

Colour: green 60% (60 lines/cm).

ISOM 1990 Definition

As ISOM 2000 but percentage tone changed from 50 to 60% and runnability band changed from 10-50% to 20-60%.

OCAD Methods

Defined as area symbol 408.0, and can be drawn with any drawing tool.

Care is needed at joins, overlap only where it is safe (usually if it is the same colour and always if it is the same symbol). If you need to share a common boundary with another symbol, draw along the edge with the control key to follow it exactly.

Drawing Considerations

The runnability depends on the nature of the forest (density of trees/brushwood and undergrowth- bracken, brambles, nettles, etc.) but does not take account of marshes, stony ground etc. which are shown by separate symbols. There is a runnability topic.

See minimum dimensions but specifically -

- Smallest area enclosed by a dotted line: 1.5mm (diameter) with 5 dots.

- Smallest area of colour green dot screen: 1.0mm˛.

Permissible Combination of Screens

The ISOM lays down the permissible combination of screens.

Forest (difficult to run) is allowed with broken ground, stony ground, marsh, and indistinct marsh,

but not with uncrossable marsh, open land, open land with scattered trees, rough open land, rough open land with scattered trees, forest: slow running, undergrowth: slow running, undergrowth: difficult to run, or vegetation: very difficult to run.

Pictorial Descriptions

- BOF Rules, Appendix One

Thicket: an area of forest where the tree cover or undergrowth is so dense that it is difficult to pass.

Felled area: an area of felled or fallen trees.

Click to go to the top of this page

International Specification for Orienteering Maps produced by the International Orienteering Federation
OCAD produced by Hans Steinegger Software. © 1988-1999 Hans Steinegger. ® OCAD is a registered trademark of Hans Steinegger
This document has been written and coded by Peter Hornsby of Ashby Mapping
Apologies for any mistakes and errors; please inform details of any problems, thanks.
Produced for the Ashby Mapping internet site on 20 November 1997 and 1 December 1999  ©1997-2000 Ashby Mapping
Revised 28 December 1999, 23 March 2000