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101 Contour

ISSprOM 2019-2
101 Contour (ISSprOM 2019-2)

Geometry: line.


A line joining points of equal height. The standard vertical interval between contours is 2 or 2.5 m. To emphasize the 3-dimensional effect of the contour line image, contour lines shall be represented as continuous lines through all symbols, also Building (521) and Canopy (522).

Slope lines may be drawn on the lower side of a contour line to clarify the direction of slope. When used, they should be placed in re-entrants.

However, contour lines shall be cut out for better legibility, if they touch the following symbols: Small earth wall (105), Small depression (111), Pit or hole (112), Prominent landform feature (115), Stairway (532). Contours shall be adapted or broken in order not to touch symbols Small knoll (109) or Small elongated knoll (110).

The relative height difference between neighbouring features must be represented on the map as accurately as possible. Absolute height accuracy is of less importance. It is permissible to alter the height of a contour slightly if this will improve the representation of a feature. This deviation should not exceed 25% of the contour interval and attention must be paid to neighbouring features. The smallest bend in a contour is 0.4 mm from
centre to centre of the line.


Colour: brown.


Correct examples