See Also...407 408 ISOM Index Vegetation index previous next
revision 05/00
406 Forest: slow running
An area with dense trees (low visibility) which reduces running to ca. 60 - 80% of normal speed.
Colour: green 30% (60 lines/cm).
Defined as area symbol 406.0, 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.
As ISOM 2000 but percentage tone increased from 20% and runnability band decreased from 50-80% to 60-80%
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˛.
The ISOM lays down the permissible combination of screens.
Forest (slow running) 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, undergrowth: slow running, forest: difficult to run, undergrowth: difficult to run, or vegetation: very difficult to run
Green/yellow/parking The problem of colour clashes on printed maps is well known. Read the section in the help file on the Colour Table for full details. In essence the screen display and the printer output is not the same as the separated output.
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