Slope Angles from Map Contours
Angles from spacing of 100m contours on 1:33,300 maps
| Contour Spacing (mm) | Slope Angle (degrees) |
| 10.0 | 17 |
| 9.0 | 18 |
| 8.0 | 21 |
| 7.0 | 23 |
| 6.0 | 27 |
| 5.0 | 31 |
| 4.0 | 37 |
| 3.0 | 45 |
| 2.0 | 56 |
This table also applies to the spacing of 500ft contours on 1:50,000 scale maps.
Angles from spacing of 100m contours on metric 1:25,000 maps
| Contour Spacing (mm) | Slope Angle (degrees) |
| 10.0 | 22 |
| 9.0 | 24 |
| 8.0 | 27 |
| 7.0 | 30 |
| 6.0 | 34 |
| 5.0 | 39 |
| 4.0 | 45 |
| 3.0 | 53 |
| 2.0 | 63 |
This table also applies to the spacing of 200m contours on 1:50,000 scale maps.