Symbolize polygons according to what percentage of total area they represent

Summary

Instructions provided describe how to symbolize polygons according to what percentage of total area they represent.

Procedure

1. Generate area values for all polygon features and store them in Field A.
2. Right-click Field A, select 'Statistics', and note the 'Sum' value.
   
   

   Note:
   If interested in doing this on subsets of the data, perform a series of 'Select by Attributes' operations. For example, "Land Use = Federal". Do this for each selection set, taking note of the sum for each subset.

   
   
3. Create Field B and use the Field Calculator to attribute the entire field to populate the records with the appropriate sum value.
   
   

   Note:
    For selected subsets, calculate the field values only for the selected records.

   
   
4. Create Field C and using the Field Calculator calculate Field C equal to Field A divided by Field B.
5. Symbolize the data based on Field C.