I am using ArcMap 10.2.2 on a Windows 7 PC.

I have shapefile range data for multiple species (multiple species in one layer), and this range data is accompanied by information relevant to the species.

Some of the species I am working with have discontiguous geographic ranges. If species X has three disconnected places it lives, I have three different rows in my attribute table, with lots of redundant data (i.e. there are three rows with identical information EXCEPT the information that relates to the polygon size). Because of this, I have about 3,300 rows for ~250 species.

I would like ArcMap to combine rows based on the species, but I can't seem to figure out how to do this properly.

I've tried dissolving based on the species name field (with multipart features), but when I do this, I just get a new layer with nothing in it.

Any suggestions?

I've tried all the things suggested in How to combine rows in attribute table using ArcGIS for Desktop? but none seem to be working.

ETA: Posted these in a comment, but here are some relevant screenshots:

enter image description here

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My intended output would be for all of the highlighted rows in the first screenshot to become a single row. And I would like that done for all ~250 species.

What I'm getting when I use dissolve:

enter image description here

  • 1
    Welcome to the site. I highly recommend adding screenshots or examples highlighting what the problem is AND the intended output. What does "combing rows" look like to you?
    – Aaron
    Feb 23, 2015 at 22:14
  • It is DISSOLVE task. Make sure you are using it properly.
    – FelixIP
    Feb 23, 2015 at 22:18
  • Here's a screen shot showing some of my attribute table and the shapefiles I'm working with. I am sure I am messing up my dissolve, I'm just not sure how. I've also added a screen shot of what I'm doing with my dissolve (sorry for the crossed out file location, it has my full name in it): i.imgur.com/xHbua9Y.png i.imgur.com/P4W3jt2.png My intended output would be for all of the highlighted rows in the first screenshot to become a single row. And I would like that done for all ~250 species.
    – user47972
    Feb 23, 2015 at 22:26
  • This is what I am getting when I use dissolve: i.imgur.com/8lkNUgO.png
    – user47972
    Feb 23, 2015 at 22:33
  • 2
    What happens when you dissolve by the field "sp"? Make sure nothing is selected prior to running Dissolve
    – Aaron
    Feb 23, 2015 at 22:34

1 Answer 1


I note in your second image from the field names that you have a Join between a csv and a shapefile, and the field you are attempting to Dissolve on is from the csv. While I can't find it documented at the moment, I believe this won't work. You first need to export your joined data to a new shapefile/feature class and then run the Dissolve on that.

And as mentioned in the comments by Aaron, you always want to make sure you have nothing selected (or only the subset you want) when running a GP tool, as most honor selections and will only run on selected features.

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