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I have a shapefile containing polygons. Each polygon is defined by its postal code. I want to calculate the centroid of each polygon using Zonal Geometry.

Sadly, for some polygons there are no centroids being calculated. It is the same when I use Zonal Statistics as Table. Some polygons seem to be ignored. There are no error messages.

It would help if someone could point me in the right direction because right now I do not even know what to fix. I have ArcGIS 10.1.

Thanks for any help!

  • Zonal Geometry creates a raster. Zonal Statistics as table only creates a table - no geometry. – Chris W Jul 24 '14 at 19:34
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Sounds like you are using the wrong tool. To create a separate dataset of points that are the centroids of a polygon use the Feature To Point tool. It requires an Advanced license.

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    @user3383369 Also note the option in the tool for creating a point inside the polygon vs its centroid, as the centroid may not fall within the boundary of the polygon. – Chris W Jul 24 '14 at 19:35
  • Hey, thx for the help. I kept on trying after i asked the question and found that if i let the tool calculated the centroids for smaller groups of polygons it works fine! I think it is somehow connected to the size of the polygons because it seems to work best if the sizes in one group are similar. But anyway, i got it done! Thx – user3383369 Jul 28 '14 at 8:59
  • and i just realised what your answer means and it works great! it is a much better way to do it! – user3383369 Jul 28 '14 at 11:21
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Alternatively, if you do not have an Advanced license and you do want centroids even if they fall outside the shape, there is another slightly more involved method.

  1. Open the polygon attribute table and create two new fields, X and Y.
  2. Right-click on each one in turn and use Calculate Geometry to calculate the respective X centroid coordinate and Y centroid coordinates.
  3. Use the Add XY Event Layer with that table as an input to create points out of those coordinates.
  4. Export the result to a new shapefile for permanance.

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