Use Split tool without splitting overlapping input features

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10-09-2015 08:56 AM
JeffThomas
New Contributor II

The Split tool splits input polygons where they overlap each other instead of just where they are crossed by the split polygons. This is frustrating because the tool help does not indicate this behavior. Is it possible to configure the Split tool to not split overlapping input features? Different tool or process? I attempted to create a model that iterates through each input feature before applying the split, but this seemed horribly slow/inefficient and I killed the process before it completed, so I'm not sure if it was even working. Thanks!

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DanLee
by Esri Regular Contributor
Esri Regular Contributor

Hi Jeff, I have tested Split tool and I see what you described: when input features contain overlapping polygons, they are broken into polygons representing the non-overlapping areas and overlapping areas in the output; the overlapping areas are duplicated. I checked with our team, this behavior is by design. Perhaps a simple way to explain this is that the tool not only splits input features but also ensures the output features are topologically correct (or clean). This behavior has existed since the tool was created many years ago; some users do appreciate this behavior while others may not. The Clip tool used to have this behavior but not anymore. I would suggest the following:

  1. Please go to Esri's Ideas web site and post an enhancement request.
  2. There may be various ways of work around the problem.
    • Make sure you have a unique value field in the input features. After using Split tool, run Dissolve on the results using the unique value field as dissolve field to get the broken polygons merged.
    • Or, use Clip tool instead Split. You would need to iterate the split polygons to clip the input one area at a time and manage the naming of the outputs through a list. Check ModelBuilder help topics if necessary.
    • If you are familiar with Python coding, there is a good on Intersect, Clip, etc. to use geometry method to avoid using the heavy duty TopoEngine by the tools. With minor modification of the sample code posted there, you can achieve what you need. http://blogs.esri.com/esri/arcgis/2013/05/20/are-you-sure-intersect-is-the-right-tool-for-the-job/

I can make suggestions to our team:

  • Add information about this behavior in the Split tool reference.
  • Monitor the votes on the Ideas site once you have posted the enhancement request.

Please let me know if you have further questions. Thanks.

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2 Replies
WesMiller
Regular Contributor III

Is it possible to post a picture of what you're talking about?

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DanLee
by Esri Regular Contributor
Esri Regular Contributor

Hi Jeff, I have tested Split tool and I see what you described: when input features contain overlapping polygons, they are broken into polygons representing the non-overlapping areas and overlapping areas in the output; the overlapping areas are duplicated. I checked with our team, this behavior is by design. Perhaps a simple way to explain this is that the tool not only splits input features but also ensures the output features are topologically correct (or clean). This behavior has existed since the tool was created many years ago; some users do appreciate this behavior while others may not. The Clip tool used to have this behavior but not anymore. I would suggest the following:

  1. Please go to Esri's Ideas web site and post an enhancement request.
  2. There may be various ways of work around the problem.
    • Make sure you have a unique value field in the input features. After using Split tool, run Dissolve on the results using the unique value field as dissolve field to get the broken polygons merged.
    • Or, use Clip tool instead Split. You would need to iterate the split polygons to clip the input one area at a time and manage the naming of the outputs through a list. Check ModelBuilder help topics if necessary.
    • If you are familiar with Python coding, there is a good on Intersect, Clip, etc. to use geometry method to avoid using the heavy duty TopoEngine by the tools. With minor modification of the sample code posted there, you can achieve what you need. http://blogs.esri.com/esri/arcgis/2013/05/20/are-you-sure-intersect-is-the-right-tool-for-the-job/

I can make suggestions to our team:

  • Add information about this behavior in the Split tool reference.
  • Monitor the votes on the Ideas site once you have posted the enhancement request.

Please let me know if you have further questions. Thanks.