topic Merge or dissolve polygons? in ArcGIS Explorer Desktop Questions

Merge or dissolve polygons?

AnnaRoberts — Wed, 22 Aug 2012 18:18:38 GMT

I've having trouble merging (dissolving?) polygons. I have 6 zip codes that I want to aggregate into one area (to make them more similar to the zips around them). I've tried using merge and dissolve, both on the original layer and on a layer of just these six zip codes, and they don't merge or dissolve. Each polygon remains intact. I think dissolve is what I really want to do - to dissolve the boundaries between the polygons so that they're all one - but if there is a better tool for this, I'd like to know. Otherwise I must be missing something...can anyone help? Thanks.

---- update ----
Okay, after trying to figure this out, then posting here, then going back to it, it suddenly fell into place. When using Dissolve, DON'T use the optional Dissolve Fields, and DO use the Statistics Fields.

Re: Merge or dissolve polygons?

AnnaRoberts — Wed, 22 Aug 2012 18:26:28 GMT

I still have a question, it appears. How can I dissolve *just* a selection from the layer? Selecting only the 6 zip codes I want does dissolve them, but it also gets rid of all the rest.

Re: Merge or dissolve polygons?

EricBowman — Mon, 27 Aug 2012 18:34:14 GMT

Hi Anna,

Try doing a selection layer first on the 6 zip codes. Then do the dissolve on that selection layer.

Hope this helps.
Eric

Re: Merge or dissolve polygons?

AnnaRoberts — Wed, 26 Sep 2012 14:55:01 GMT

Alright. So it works if I create a new layer with the polygons I want to dissolve together, dissolve them, merge them to the old polygon layer, and delete the old polygons that are still there underlying the new dissolved polygon in the same layer. It just feels like I'm missing something obvious, like there should be an easier way than to manually keep track of which ones I need to go back and delete once I've dissolved the ones that needed to be combined. Like a counterpart to the "cut polygons" would be a "combine polygons".