GIS is not my full time gig and I’m a bit stuck.

I have two layers, both with the same fields with the exception that my primary layer has extra fields and is based on a different set of polygons.

How do I intersect or join (specific fields from) my primary layer and my secondary layer without having new fields (tacked on the end) and a new output layer?

I have tried intersect and join/spatially join and they both work in that the data from from secondary layer is joined or intersected but in a new output.

What I want to do is be able to mash the identical fields from both layers and suck the attribute data from my secondary layer into my primary layer (as it does in intersect) without creating a new output and duplicating fields.

I’d also like to be able to do this after I add a new polygon to my primary layer.

I use both ArcMap and ArcGIS Pro and know nothing about scripts if that helps.

  • Field mapping is one way. For example merge and then dissolve, in the dissolve use field mapping
    – Bera
    Commented Jan 23, 2021 at 12:50
  • Hide most identical fields in second layer, keep joining field. Use tool "Join Field", this will bring required layers from second to first layer. Do it from mxd, so you can hide fields.
    – FelixIP
    Commented Jan 24, 2021 at 4:32

1 Answer 1


It sounds like you want to append your secondary layer to your primary layer. Lets say for instance you have Table A with fields: Make, Model, Year, and Color. You also have table B with fields: Make, Model, and Year, but no Color field. You want to transfer the contents of table B into table A. By using an append, the contents of table B can be appended to the end of table A. Any fields in Table A that are non-existent in Table B will receive a value of NULL after the transfer. Look at my table example below. You can also define custom field mappings. Check out the documentation link below!


Screenshot showing Table A and Table B

Screenshot showing Table A and Table B

In the append tool, you must choose "Use the field map to reconcile field differences", then you must click the "x" on the field that does not exist in table B, thus removing it from the field map. Once removed, corresponding records after the append will have a value of NULL in that field.

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Screenshot showing append tool after field is removed from field mapping

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Resulting table after append

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  • If the user wants to conflate attributes, Append is the wrong solution -- topological overlay is not required (Identity/Intersect, vice Spatial Join), but adding additional features isn't going to help.
    – Vince
    Commented Sep 21, 2022 at 17:10

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