What is the best practice for erasing overlay geometry? My scenario is: I have a polygon layer with 1000 features. i need to create a tool from model builder that select polygons with user defined attributes, and verify if there is any other polygons are overlapping. Then erase the overlay area from overlay polygons.

EX: Polygon A is selected by attributes and polygon B is overlapping with A. Erase overlapping area from B.

I am able to find the overlapping polygons, but when i use Erase tool it is creating new feature class but i need output should be modified with in the same feature class. This is nothing but Clip in Edit toolbar with "Discard the area that intersects".

  • So are polygons A and B in the same feature class?
    – GISGe
    Jul 15, 2014 at 9:24
  • yes, both are in one feature class.
    – Chenna
    Jul 15, 2014 at 9:25

1 Answer 1


The simplest solution is probably to create a topology with the Must Not Overlap rule, select all errors in the Error Inspector window, right-click and choose Substract:

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You can find out how to create a topology here if necessary. You can create the topology, add feature classes and rules with ModelBuilder with the tools from the Topology toolset, but you must correct errors manually in an edit session (you can solve them all at once). By selecting all errors and solving them using Substract, you delete all overlapping polygons, there will be a gap instead of an overlap. If you don't want gaps, you should use the Merge solve option, but this fix must be applied individually because you must determine which polygon the overlap must be merged to... If there is a criteria to to determine which polygon the overlap should be merge to, this can be automated.

  • This can be done from Model Builder? Subtract removes from Which Polygon?
    – Chenna
    Jul 15, 2014 at 10:50
  • @Chenna - See updated answer
    – GISGe
    Jul 15, 2014 at 11:26
  • great, I am trying to implement this method; to avoid user interaction. so is there any chance that i can automate the whole process?
    – Chenna
    Jul 15, 2014 at 12:26
  • If you can define a rule, like e.g. merging the overlapping polygon to the largest adjacent polygon, yes. But you will more than probably need arcpy.
    – GISGe
    Jul 15, 2014 at 12:30
  • if you can provide a sample snippet on arcpy would help me greatly.
    – Chenna
    Jul 15, 2014 at 13:45

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