Multi Direction Hillshade

A number of workers have worked with multi direction hillshades, which average several different sun positions.  Improvements will probably be subtle, and unless the terrain itself is the object, and not providing a base map to provide context for other layers, it may not be worth the effort. 

Implementation in MICRODEM

• Bring up the hillshade options
• Pick the number of directions to average
• They will share the same elevation for the light
• One will have the azimuth specified on the form, and the rest will be evenly spaced.

References

• https://pubs.usgs.gov/of/1992/of92-422/of92-422.pdf (GDAL uses this algorithm)
• Kennelly, P. and J. Stewart. 2013. General Sky Models for Illuminating Terrains. International Journal of Geographical Information Science. 28(2): 383-406.
• Terrain Tools Sample v1.1 for ArcGIS: https://www.arcgis.com/home/item.html?id=4b2ea7c5f87d476a8849c804b81667aa  222 MB Python scripts

Last revision 10/26/2017