See Also...309 308 ISOM Index Water and marsh index previous next
revision 05/00
310 Marsh
A crossable marsh usuallytwith a distinct edge. The symbol should be combined with vegetation sybols to show runnability and openness. Where a small marsh are should be combined with either 403/404 it is permitted to use 401/402 to improve legibility. The smallest marsh should be shown by at least two lines on the map.
Colour: blue (with yellow/green).
Line width 0.1mm
Line spacing 0.2mm (0.3mm line to line) . Minimum two lines of 0.5mm
This symbol is oriented to north.
A crossable marsh with a distinct edge. Symbol 310 may be combined with symbol 403 for clearly open marshes. For densely wooded marshes symbol 310 may be combined with symbols 406-410. The smallest marsh should be shown by at least two lines on the map.
Colour: blue (with yellow/green).
Line width 0.125mm
Line spacing 0.25mm (0.375mm line to line)
This symbol is oriented to north.
A small two line marsh is defined as point symbol 310.1, can be drawn with any drawing tool, beware this is a rotatable symbol.
The larger marsh is defined as area symbol 310.0, and can also 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.
Underlying area colours will show through the symbol in the spaces between the blue lines, no user intervention needed!
These combinations are based on the ISOM1990, they will be updated shortly, if you need to view the 2000 soecification combinations see the combinations page.
The ISOM lays down the permissible combination of screens.
Marsh is allowed with rough open land, rough open land with scattered trees, forest: slow running, undergrowth: slow running, forest: difficult to run , undergrowth: difficult to run, and vegetation: very difficult to run,
but not with broken ground, stony ground, uncrossable marsh , indistinct marsh, open land, or open land with scattered trees.
either:
Marsh: A permanently wet area with marsh vegetation.
or
Small marsh: A clearly defined marsh of less than 10m diameter.
or even
Firm ground in marsh: A non-marshy area within a marsh, or between two marshes.
If this symbol is used in a yellow area, especially a full yellow area (open land), then it will tend to green out, as both the blue and the yellow will print.
If you use the colour table hint to knockout the yellow, as described in the full blue topics, then there could be a problem with white edges to the symbol with any print misregistration.
There are more details in the Main Help File or in the Colour Help file.
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