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I am trying to create a single continuous (neighborhood) polygon from many tax block parcels. The Multipart to Singlepart GP tool does not accomplish the task since I need the polygon to be complete; i.e., without the spatial gaps between the parcels (see image). Any ideas of a quick and dirty way to accomplish this?

Parcels

  • possible duplicate of Removing small spaces between polygons – Evil Genius Nov 8 '13 at 20:10
  • This is an interesting question. I would almost suggest a Union then Dissolve workflow, but this will only create a single continuous polygon if the features you have originally selected are touching. How would the software know the exact bounding geometry without making mistakes? – GeoGhost Nov 8 '13 at 20:15
  • @Evil Genius, as per the cited thread the Eliminate tool did not produce the desired results. Minimum Bounding Geometry also did not give me what I'm looking for. – mikeLdub Nov 8 '13 at 20:35
  • 1
    also, this is to assist a coworker, so pretty much wedded to Esri here. – mikeLdub Nov 8 '13 at 20:36
  • Doesn't sound like this will be possible without ArcInfo. – BradHards Nov 8 '13 at 21:51
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You could use the Aggregate Polygon GP Tool. You'll need an Advanced license though.

  • so far, this tool has brought me the closest to my desired result, but still have some holes and gaps. – mikeLdub Nov 12 '13 at 16:41
  • I haven't played around with this tool much. I would think that you could get ride of the holes using the minimum_hole_size variable. As for the gaps, does setting the orthogonality_option to ORTHOGONAL help? – travis Nov 12 '13 at 21:59
  • yup tweaking the parameters got me to arrive at the single "neighborhood" polygon. thanks – mikeLdub Nov 13 '13 at 20:23
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Method 1

Select the polygons to include, buffer them all by at least half the largest gap among them (but only by a very little bit more), union the buffers, and negatively buffer the result by the same buffer radius.

The only errors made will be that concave indentations around the perimeter will be slightly smoothed (faired with circular arcs). One way to clean them up (if needed) is to repeat the procedure on all the other polygons. Subtract its result from the original result. This creates a solution that errs in the other direction: the convex outside corners will be smoothed. Fix them by unioning this result with all the original polygons: that will sharpen all those corners without adding any unnecessary junk.

Method 2

Union the polygons to include and compute a "concave hull" for them.

  • thanks @whuber, I am trying your Method 1, but consistently getting errors that read Warning: Empty Output Generated. I found this, so I repaired geometry but I still receive the same error in the final buffer despite re-repairing geometry. – mikeLdub Nov 12 '13 at 16:40
  • If the problem occurs at the final step of negative buffering, then Jakub's answer might be helpful in this regard. Have you tried a slightly less aggressive negative buffer? Using a slightly smaller radius at the last step ought to guarantee there are no null features created. – whuber Nov 12 '13 at 17:37

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