Topographic relief, particularly mountains, have four important elements...
- Relative elevation Height of mountains above adjacent land.
- Elevation Height above sea level. For decorative maps, elevation is less important than relative elevation.
- Average slope Steepness of the mountains is important to the human experience. When walking we are very sensitive to steepness and the effort required to walk up or down.
- Texture Spacing of mountain features such as small rivers, rock outcrops, moraines, etc.
For decorative maps it is generally better to represent mountains with a profile, or side-view. Make the profiles relate the four elements above. Don't show every hill and valley. Don't worry about making each mountain perfectly in place.
Incorporate vertical exaggeration
In other words, make mountains taller and steeper than they really are. Humans are more sensitive to up and down of the landscape.
Here are some symbols from his book Principles of Cartography
Notice that the mountain symbols can be made proportional in size to reflect relative elevation. They are also able to capture slope by the visual steepness of the slope. The texture can be represented by the density of the mountains.
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