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Legend & Symbology options for displaying transparent polygons

December 18 2008 | 0 comments
Categories: ArcGIS Methods, Cartographic Effects, Map Elements

I have two questions regarding polygons...

a) Often, when overlaying polygon features on a raster imagery, it is preferable to keep the outline solid while making the interior transparent. Is there an automated way of doing this or is it always necessary to add the same file as two separate layers with different symbology? When using this method, I have to create a 3rd, "phantom layer" to properly depict the other two in the legend. All of this just feels like sloppy cartography.

b) Is there any way to change how a polygon is represented in the legend? There are many times the default settings don't adequately depict what I'm representing. Often, a rectangle doesn't depict an organically shaped feature very well and can lead to confusion.


Mapping Center Answer:

I'm going to restate #1 just to ensure I've understood correctly.  When you make a polygon layer transparent, the transparency is applied to both the fill and the outline--often defeating the purpose of the outline--to distinguish where one polygon feature ends and another begins.  In this case the two separate layers method is the correct way to get the job done, where the outline layer is drawn above the fill (transparent) layer.  One trick to avoid having to do to the 3rd "phantom layer" is in how you name the other two layers.  For instance might name my transparent tinted zoning polygons "Zoning Class" and the outline layer "Zoning Boundaries" 

For #2, the answer is yes.  The term we use for that is "Legend Patch Shape".  There is a help topic that covers all the details:


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