I have 2 shapefiles; one has income data on a block group level, the other has polygons showing utility providers service areas. I would like to know the income within each utility provider area. Many of the utility service provider area polygons cross the block groups, therefore I know that only a percentage of the block group income can be attributed to the utility provider area. How do I calculate what percentage of the total block group income can be attributed to the service provider area?
I would create a feature layer using the Make Feature Layer GP tool of the block group data. Set the "Use Ratio Policy" for the financial attributes (if you have them in the table) when creating the feature layer.
Or to calculate the percentage, add a double field called "percent", calculate the field as 100 and set as "Use Ratio Policy" prior to creating the feature layer.
Then you can use the Union GP tool which will respect the field ratio setting. This should give you the actual financials or the percentage attributed to the service provider.
When Use Ratio Policy is enabled, whenever a feature in an overlay operation is split, the attributes of the resulting features are a ratio of the attribute value of the input feature. The output value is based on the ratio in which the input feature geometry was divided. For example, if the input geometry was divided equally, each new feature's attribute value is assigned one-half of the value of the input feature's attribute value. Use Ratio Policy only applies to numeric field types.
Make sure you export the Layer to make it permanent. These are automatically deleted once a session has closed.