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How do you create line symbols that vary in thickness dynamically?

March 24 2009 | 0 comments
Categories: Map Elements, Symbology

I'm trying to illustrate highway flows and I'd like for the line thickness to be a function of the flow, but not limited to any set number of categories but rather adjust thickness based on the flow field. I'd then like to create a volume scale label for the legend that provides some measure of comparison, in this case for a set number of flow categories. Any ideas?

Mapping Center Answer:

I would use graduated symbols (under the Quantities heading in the symbology tab).  The caveat there is that you'll likely need two layers:  one to show the roads as normal.  Then another that you'd symblize using graduated symbols where you've got a definition query to screen out the 0 and very low traffic count streets.  That will allow you to have a fairly standard set of classes for something like average speed, or how much the speed differs from the posted limit.

You'll need to convert your legend to graphics and construct a custom graphic to do what you want for the legend, our European Energy Map has a topic that describes how to do that. 

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