I am trying to calculate the area of floodplain within property. So when I do intersect it merges the two layers together where they intersect. But from there I don't know how to calculate the areas in the new layer, and then add that data back to property.

Essentially what I am trying to do is isolate the properties that have a certain percentage of floodplain in them.

The steps I have in my head but am lost on what tools to utilize to achieve my desired outcome:

  1. Create a new field in property called "true_area"
  2. Do calculate geometry to determine the area
  3. Intersect floodplain and property to create intersection
  4. Create a new field in intersection called "flood_area"
  5. Do calculate geometry to determine the area
  6. Some how merge property and intersection based on retained fields containing the address
  7. Create a new field in property called "percentage"
  8. Divide "flood_area" by "true_area" to get decimal value
  9. Convert to percentage with calculate field
  10. Export data to new layer "Where percentage is greater than or equal to 20

This is the scenario I believe I need to go to have the outcome I am looking for. I do not know how to do coding, this is the extent of my knowledge.

  • Summarise intersect by fid_property as case field, area totals. Join output table to property.
    – FelixIP
    Mar 19, 2023 at 19:42
  • Yes! This worked. I was messing up the join. Thanks!
    – Seth
    Mar 20, 2023 at 17:25


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