See Also...112 ISOM Index Land forms index previous next
revision
05/00
111 Knoll
Knolls are shown with contour lines. A prominent knoll falling between contour lines may still be represented by a contour line if the deviation from the actual contour level is less than 25%. Smaller or flatter knolls should be shown with formlines.
Colour: brown.
Line width 0.14mm
As ISOM 2000 but line width was 0.125mm
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 flatter knolls as appropriate.
Any drawing tool can be used, but it is now becoming common to find that all remapped areas have regular oval knolls! Use the oval tool, but edit to get the correct shape.
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.
HILL A high point, shown on the map with contours.
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