Five Ways to Depict Elevation

A digital elevation model (DEM) is merely an image where each pixel represents the average height above mean sea level for the area that it covers spatially. If displayed like normal optical images (where lower values are darker and higher values are brighter), not a lot of the terrain detail can be visualised.

That is why we usually display elevation models in other ways such as a hillshade (either greyscale or with hypsometric tinting), contours, or a triangulated irregular network (TIN). This makes it more visually pleasing and easier to distinguish different terrain features from each other.