I am working with three clipped layers that are shown in the TOC. I created these layers from a large watershed shapefile. However, each clipped layer includes the layer before it and only expands on the one before it.

I was wondering is there a way that I could combine the three layers without using the same features more than once and also at the same time assigning them different values. Pretty much as it is shown in the image that I have provided. How can I assign each clipped layer different values without repeating a feature?

I have tried using the merge tool but then I don't know how to give each features different values.

This may be a little confusing please let me know if you have any questions

enter image description here

  • Have you looked at the Analysis Tools > Overlay yet? The union command may be a good choice.
    – Aaron
    Commented Jul 18, 2012 at 20:54

3 Answers 3


The option which will allow you to retain all of your data is Union. It will 'Intersect' two layers at a time spatially while retaining all the features. Attributes are concatenated together where features overlap.

You will, in the union method, be 'duplicating' your data. After you've completed the process, make sure to look through the attribute table to make sure you understand what's happened.

You can also to a pure Intersect, but this will exclude anything that is not overlapping. I only suggest this because it may be applicable to some of your analysis.

  • I tried both the Union and Intersect tool. The Union tool unites the tables together which is good because that's what I want it to do however, it changes their values. For example, the center dark clipped layer has a value of 0, when I unite it with the tool to the second clipped layer (light purple) it changes its value to 1 and makes it equal to the second layer. I want that when I combine them they keep their values separate, meaning the center keeps the 0 value and the ones around it keep the 1 value and so on.
    – user8759
    Commented Jul 19, 2012 at 13:25
  • I feel like I need a tool that is a Union and a Merge together. The Merge tool keeps the original values (0,1 ect) but the Union tool does not overlap features. I tried uniting them together and then Merging them but by uniting them first it changes their 0,1 values =/
    – user8759
    Commented Jul 19, 2012 at 13:53

You may also want to look into building a simple model via modelbuilder since it looks like there are multiple steps to the edit you want to do.

  • 1
    Maybe create a blank feature dataset, set up the schema and then use a combination of the Erase,Append, and Calculate Field tools to create a new dataset. Maybe i'm way in left field with this one. And yes, I would do this in ModelBuilder as I also suspect any approach will require a few steps.
    – dchaboya
    Commented Sep 17, 2012 at 15:43

Something else to try is to remove the overlapping area first. If you start an edit session and select the the largest polygon you can then use the Editor tool bar clip option to discard the area that intersects it, check out this ESRI forum, http://forums.esri.com/Thread.asp?c=93&f=983&t=144813#430373. Then you should be able to merge all layers together.

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