I want to combine different layers into one but I still want to identify different layers in the new combined layer. Union is best for this, but it doesn't allow me to combine more than two layers. I am using arcgis 10.1, with site license.

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    Can you please edit your question to let us know what software, software version, and license level you're using? – Fezter Feb 25 '14 at 1:40

You say that you are using a "site license" but not whether your license level of ArcGIS for Desktop is Basic, Standard or Advanced.

If it is Advanced then Union will allow you to use more than two input feature classes.

If it is Basic or Standard then you will need to do pair-wise Unions and then Union the results instead.

To have the original FID for all feature classes preserved in the final output you should use ALL for join_attributes.

  • I have basic license. I tried pair-wise union, but that didn't work for me when I wanted to recombine the paired layers again using 'union'. I have unique attribute values in each different layers, I need to combine them by attribute so that I can still identify which layer they belong to after combining. Is there an easier or alternative way to do this? – user27321 Feb 25 '14 at 3:49
  • @user27321 Did you use ALL for join_attributes? The other two options will lose the original FIDs during or after the first Union respectively. – PolyGeo Feb 25 '14 at 4:35
  • If you want to retain FIDs I would suggest copying them to an FID2 field first, FIDs are not guaranteed to be consistent after data is edited. – AnserGIS Feb 25 '14 at 7:44
  • @AnserGIS you are right if the data is edited but this Question is only about whether Union-ing multiple feature classes can retain links through to the original feature classes. – PolyGeo Feb 25 '14 at 7:47
  • Fortunately, I had advanced license and could run 'union' for multiple layers. That didn't completely solve my problem as union was not done based on a intended field. I had to copy/paste and modify fields later on attribute table. – user27321 Feb 28 '14 at 19:45

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