Ask A Cartographer

Symbolize data using 2 values

August 11 2009 | 0 comments
Categories: Map Data, Symbology

I was given the task of classifying a data set based on specific data range (these would be color coded). At the same time, the size of the symbol for this color coded data set would be based on another data range. Essentially producing a color coded proportional symbol based on two data ranges. Is this possible?
Any help would be greatly appreciated.

Mapping Center Answer:

Unfortunately there is no simple way to do this.  If you can add another field to your data that contains class IDs, then you can use the quantity by category symbology method, where the class IDs would be unique values.  Then you'll also need to customize the legend.  So, it's a good bit of work, but possible.  To help with storing the class IDs, try something we wrote in a Mapping Center blog entry on thematic maps and representations.  The key bit there is that when you store the symbols of a thematic map like a choropleth display based on Graduated Colors symbology, the class IDs are automatically stored in the RULE_ID field for the representations.  That means you can use them as the basis for unique values symbology.  It's a bit of a hack-workaround, but much faster than doing so manually.

If you would like to post a comment, please login.

Contact Us | Legal | Privacy |