At ArcGIS Desktop 10.5, I have a polygon file geodatabase feature class. Many of its polygons are spatially coincident; that is, if I click on a single polygon in Arcmap to select it, the resulting selection will have multiple records, all sharing the same exact polygon outline. Here's a screenshot example where one polygon is selected, resulting in 74 selected records. In my mind, they represent 74 polygons stacked upon each other.

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The attribute table contains a long integer field, noise_value. I need to sum this field for each input polygon, which, as I mentioned above, may be comprised of multiple spatially coincident polygons, and output the result to a new, flattened, polygon feature class containing the summed value.

In my example, the 74 overlapping polygons would be reduced to a single output polygon with a summed noise_value. Of course, this summation would have to be repeated for all input polygons.

I've tried these approaches, and all have failed:

1. Flatten the input feature class while applying the field map merge rule "SUM" for the noise_value attribute.

I tried this approach with the Feature Class to Feature Class tool as well as the Merge tool. In each case the output was identical to the input; no flattening or summing occurred.

2. Create a flattened output feature class and then spatially join it to the original feature class, summing by noise_value with field map merge rule SUM.

I tried this approach with the Feature to Polygon tool, and also with the Union tool to create the flattened output feature class. Both cases failed, with a "Topoengine error". Research indicates that this type of error can be traced to inadequate hardware resources, but I'm using a computer with an i7 processor, 16GB ram and a 1 TB SSD.

3. Use the Dissolve tool (@BERA's suggestion) with noise_value as the statistics field and Statistics Type = SUM.

Since what I want to do is flatten (dissolve) the geometry, I left the Dissolve Field blank. The result did not work for me because it created a single output polygon with one overall summed noise_value.

I've run out of ideas, and am looking for advice.

  • You should take a look at the dissolve tool – BERA Jun 30 '17 at 18:25
  • If you want more than one polygon after a dissolve, I'm fairly certain you need to select something in the Dissolve field. – Brynne Jun 30 '17 at 20:02
  • Add geometry attributes, centroid. Concatenate them into single text field. Apply dissolve on this field. Consider rounding coordinates using something like gis.stackexchange.com/questions/125090/… – FelixIP Jul 1 '17 at 0:44
  • @FelixIP, perfect! Calculating the centroid is a great way to do a geometry dissolve. In my dissolve on the centroid, I used noise_value as the statistics field with statistics_type = SUM. The result was just what I was looking for. If you want to reform your comment as an answer, I'd be happy to give you credit. – Stu Smith Jul 1 '17 at 15:44

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