Hillshades are used to portray the three-dimensional (3-D) aspect of a dataset by adding shadowing effects, commonly applied to elevation and bathymetry. This can be used alone or in combination with an overlay that provides color shading of the underlying data values.
|Overlay:||Hillshade:||Overlay + Hillshade:|
The above examples show land elevation with higher elevations in orange and lower elevations in blue. Using a hillshade enhances depth perception.