See Also...115 116 ISOM Index Land forms index previous next
Depressions are shown with contours or form lines and slope lines. Prominent depressions falling between contour lines may be represented by a contour line if the deviation from the actual contour level is less than 25%. Smaller or shallower depressions should be shown by form lines.
Line width 0.14mm
As ISOM 2000 but line width was 0.125mm and the ISOM number has changed (was 113)
No symbol is provided in the default.ocd symbol set. The feature may be drawn by using symbol 101, contour or 103, form line for normal or shallower depressions as appropriate.
See the topic on slope lines for the tags in the depression.
Check the general comments on land forms note especially the following:-
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.
With careful editing some form lines and knoll/depression groups can be generalised with contours to improve legibility.
A hollow from which the ground rises on all sides, shown on the map by contours.
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