Stony or rocky ground which reduces the runnability significantly (to about 20-60% of normal speed).
The dots should be randomly distributed but not interfere with the representation of important terrain features and objects.
Illustration serves as an example of density and also point symbol (single dots) can be used to draw stony ground.
To avoid confusion with symbol Distinct vegetation boundary (416), the dots should not be arranged to form a line.
The minimum number of dots is three (footprint 8 m x 8 m).
The maximum distance (centre to centre) between neighbouring dots is 0.40 mm.
The minimum distance (centre to centre) between neighbouring dots is 0.32 mm.
Density: 6-8 dots / mm².