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Symbolizing unique values from a combination of 4 or more fields

December 20 2007 | 0 comments
Categories: ArcGIS Methods, Map Data, Symbology

Map Symbology - The symbology tab in the Layer Properties dialouge box offers the option of symbolizing unique values in up to 3 fields. Is there a quick work-around when you have 4 fields with unique values?

Mapping Center Answer:

I’m afraid there is nothing particularly quick. If you are ArcObjects-inclined, then you should know that the system is implemented such at you can use any number of fields.

To work around this user interface limit, you can combine the values of your many fields into one new field, and just use that field. To do that use the Add Field tool to add a new Text field that is at least as wide as the widest combination of information in the other fields. Next use the Calculate Field tool and concatenate the values from the other fields using an expression like:

[Field1] & “, “ & [Field2] & “, “& [Field3] & “, “& [Field4] (this for personal geodatabases)

“Field1” & ‘, ‘ & “Field2” & ‘, ‘ & “Field3” & ‘, ‘ & “Field4” (this for Shapefiles)

Generally it’s much better if the values in your fields are descriptive, e.g., text, rather than just numbers, as you’ll need to translate the numbers to something meaningful for your legend.

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