Ask A Cartographer

Adjust the transparency of a layer within a custom line/fill symbol

July 02 2008 | 0 comments
Categories: Symbology

Apologies, but I am a total beginner. I am trying to make a custom line/fill symbol and I would like to adjust the transparency of individual components of my fill. For example, I would like to have several tint bands that are slightly transparent, but then I would like to have a hash line or solid line that is not transparent. I am looking at Cynthia Brewer's latest book and I believe she refers to these tint bands as 'offset transparent bands', but I can not figure out how to adjust the transparency of individual components without affecting the overall transparency of the entire symbol.

For example, she suggests a 40% transparency in one band and a 60% transparency in another...

Any help would be greatly appreciated!

Mapping Center Answer:

To achieve the effect you've described, you will need multiple layers (put them in a group layer afterwards if you want to make your TOC easier to navigate).  That is to say, there is no way to set the transparency for one layer in a symbol versus another layer in a symbol.

The uppermost layer would be your layer with a line fill with "hash or solid line that is not transparent".  The next layer down would be a line fill with one or more transparent bands. If you can use the same level of transparency for all the bands, then this is the only other layer you'd need.  Meaning, that for each different level of transparency you'll need to replicate your layer an additional time.

To save time and frustration, prototype a single layer with exactly the symbol you want in terms of bands/lines that will give you the information (offsets, angles, and separation values) to create the symbols for the individual layers that support the transparency you want.

Last, many of the examples in Cindy's book, Designed Maps, were not done with ArcMap, and while the vast majority of the effects can be contrived in ArcMap, a few cannot, and some of those that can will require some time and create approaches.

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