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I'm using ArcMap 10.3.

I have a layer of different land use types. After calculating the percentage of each land use in the catchment using tabulate intersection, I found out that the percentage of total land use is larger than 100% which indicates that polygons are overlapping each other. I managed to find all overlapping polygons using intersect. The result of intersect is shown below.

Could you please let me know what is the best way to fix all these overlap?

enter image description here

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2 Answers 2

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the quick and dirty method consists in using the "union" tool with the layer alone. Two new polygons will be created where polygons are overlapping and you can remove one of them. This is not straightforward but you can use "find identical" to get the polygons to be deleted.

The more advanced solution consists in building a topology for your layer (with the mustn't overlap" rule), then you can using the topology fixing tools.

Subtract: The Subtract fix removes the overlapping portion of geometry from each feature that is causing the error and leaves a gap or void in its place. This fix can be applied to one or more selected Must Not Overlap errors.
Merge: The Merge fix adds the portion of overlap from one feature and subtracts it from the others that are violating the rule. You need to pick the feature that receives the portion of overlap using the Merge dialog box. This fix can be applied to one Must Not Overlap error only.
Create Feature: The Create Feature fix creates a new polygon feature out of the error shape and removes the portion of overlap from each of the features, causing the error to create a planar representation of the feature geometry. This fix can be applied to one or more selected Must Not Overlap errors.

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    While the Union method does take care of overlapping polygons, you should also look for slivers, gaps between polygons. You could create a polygon covering your study area and use Erase with all of your land use types on it, to get areas where there "is no" land use.
    – Martin
    Sep 16, 2015 at 8:54
  • @radouxju Many thanks for your time and help. That's exactly what I was after. However, in case I have many small errors (1000 small overlapping polygons), is there a way to fix all the errors at once?
    – shiny
    Sep 16, 2015 at 12:50
  • with the union or the topology method ?
    – radouxju
    Sep 16, 2015 at 12:56
  • @radouxju The topology method.
    – shiny
    Sep 16, 2015 at 13:39
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Also find out if your layer has Multipart polygon by using the tool (Multipart to Singlepart) if there are multi polygons then delete them.

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  • Welcome to GIS SE! As a new user be sure to take the Tour. My concern with your answer is that a layer (including this one) may have multipart polygons that do not overlap so while I agree that they are well worth being aware of, they should not be indiscriminately deleted.
    – PolyGeo ♦
    Sep 16, 2015 at 11:10

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