[GIS] How should I correctly exaggerate a hillshade raster (ArcGIS10, Spatial Analyst)

arcgis-10.0cartographyhillshaderasterspatial-analyst

I once wanted to generalize a high resolution raster and instead of MEAN i accidentally selected the default SUM technique, using a cell factor 5 (Lidar DEM is 1m resolution). When I used this result as input to the hillshade funciton what I got was what I can only describe a highly exaggerated hillshade. I deleted the results and recreated the generalized DEM but now I have the need to show more exaggerated terrain characteristics in a topographic map and it seems to produce the results I want albeit generalized. Is this a common way to do this or should I be using a different technique?
How would I exaggerate a DEM without having to aggregate the raster?

Hillshade created from generalized (Mean, Cell factor 5) LiDAR DEM
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Hillshade created from generalized (SUMm Cell factor 5) LiDAR DEM
enter image description here

Best Answer

Since hillshade is just an overlay, you can do it anyway that gives you the desired result. However, the usual way to emphasise the terrain is to apply a vertical exaggeration. In ArcGIS you use the 'Z-factor' in the hillshade tool to do this as per the documentation here. You multiply the z conversion factor by the exageration factor. If your z-units are the same as your distance units then it will default to 1 and you can then treat it just as an exageration factor.

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