Ask A Cartographer

Polygon extrusion/illumination

November 17 2009 | 1 comment
Categories: Cartographic Effects

This is a graphic of now unknown origins which depicts a polygon which has a raised up effect along with a sophisicated shadowing. It is more involved than that described on the Oregon Earthquakes map.

Mapping Center Answer:

Yes, but not much more complicated than what is shown in the Oregon Earthquakes example.  Instead of one polygon with one level of transparency, the map you show can be done by using the Buffer tool to create progressively larger, though only slightly larger buffers that are set to be transparent--you should need 7 to 12 buffers to make the effect look good (the larger the shadow, the more buffers you will need). 

Optionally, you may also want to use the Erase tool with the original polygon being erased from your area of effect polygon.

Will not work with raster posted by Kelly Larvie on Jan 14 2010 12:10PM
As mentioned in another post (somewhere) there is an error with transparency of the top layer if it has rasters in it. Has there been any fix for this?

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