How a hillshade map turns elevation data into readable terrain relief
A hillshade map revealing terrain features through simulated illumination.
How Hillshade Works
The algorithm places a virtual sun at a specific position in the sky, defined by two angles:
- Azimuth (compass direction, typically 315° for northwest)
- Altitude (height above horizon, typically 45°)
For each cell in the elevation model, it calculates the angle between the surface normal and the incoming light rays. Surfaces facing the sun render bright; surfaces facing away render dark; surfaces at oblique angles render in intermediate grays.
Why Hillshades Are So Effective
This simple calculation produces remarkably effective visualizations. Subtle features that are invisible in raw elevation numbers pop into view when illuminated from the side.
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Ancient Features
Ancient field boundaries, archaeological sites, and historical structures become visible through subtle elevation changes.
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Geological Structures
Fault lines, erosion patterns, and geological formations appear clearly when shadowed by virtual sunlight.
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Human Intuition
The human visual system is extremely good at interpreting shaded relief, making hillshades one of the most powerful ways to communicate terrain.
Applications
Hillshade maps serve professionals across multiple disciplines:
LIDARVISOR OUTPUT
Hillshades with LidarVisor
LidarVisor generates hillshade visualizations automatically from your DTM.
View them draped over 3D terrain or export high-resolution images for use in reports, presentations, and GIS projects.
For reports and presentations, a well-rendered hillshade communicates terrain more effectively than any table of numbers.
Hillshade map of valley terrain showing drainage patterns and subtle elevation changes.