Slope Angles from Map Contours



Angles from spacing of 500ft contours on 1:50,000 maps


Contour Spacing (mm) Slope Angle (degrees)
10.0 17
9.5 18
9.0 19
8.5 20
8.0 21
7.5 22
7.0 24
6.5 25
6.0 27
5.5 29
5.0 31
4.5 34
4.0 37
3.5 41
3.0 45
2.5 51
2.0 57

Angles from spacing of 200m contours on metric 1:50,000 maps


Contour Spacing (mm) Slope Angle (degrees)
10.0 22
9.5 23
9.0 24
8.5 25
8.0 27
7.5 28
7.0 30
6.5 32
6.0 34
5.5 36
5.0 39
4.5 42
4.0 45
3.5 49
3.0 53
2.5 58
2.0 63

This table also applies to the spacing of 100m contours on 1:25,000 scale maps