ArcGIS Pro "Summarize Within" Geoprocessing Tool Giving Incorrect Results

[MitchHolley1]

I have run the "Summarize Within" GP tool in ArcGIS Pro 2.3.3 and it seems to be giving incorrect results.  The input is a Parcel feature class with a definition query applied to only show one parcel.  The summary polygon feature class is representing a site that also has a definition query applied.  After running the "Add Geometry Attributes" GP tool, the [POLY_AREA] field reads '124999.66403816' (see image 1).  But, after running the "Summarize Within" tool, the summary area found in the result table reads '125018.31814394'.  Does anyone have any idea why?

1.) Before running "Summarize Within" with inputs

2.) Result table after "Summarize Within" tool is complete

[RalfWessels]

Hi Mitch,
looks like you have a similar problem with the tool as I do.
In a test I found that calculating areas with "Add shape summary attributes" gives a different result than the "Summary Fields" > Sum "Shape_Area" method in the same tool.
The result with the method "Add shape summary attributes" (which you also used) is definitely wrong. Only with the method "Summary Fields" > Sum "Shape_Area" the correct result is output (see screenshot).
How can it be that when using Summarize Within 2 different results are output?
Are different calculation methods used here for the area calculation?
Is this a bug?

I use ArcGIS Pro version 2.8.3
The coordinate system used in the map and the polygons stored in a file geodatabase is UTM Zone 32N (EPSG:25832).

Best regards from Berlin
Ralf

Translated with www.DeepL.com/Translator (free version)

[KaraUtter1]

I am having this same issue. When I run the Summarize Within and add Shape Summary Attributes in acres, it's calculating about 500 acres off from the number that calculates when I run a Calculate Geometry for acres on the same shape. This is definitely a problem. I'm using a state plane projection in feet, so I this is not a GCS issue with converting degrees to other units, it's definitely a bug in the geoprocessing tool itself.

@JanCunningham 

[ajohnson]

Has anyone resolved this issue? I'm still running into this error with summarize within.

[KaraUtter2]

I don't believe they are working on this as an issue or bug to be fixed. I spoke with tech support and they said the results are expected because they are "weighting" the summary. This makes zero sense. As GIS professionals we are trying to be as accurate as possible given the limitations of projections and other, but how can we even provide a good estimate value if it's being 'weighted' by some mysterious factors we can't control?? I'm not sure where to take the complaint from there?

[CharlottePeters95540]

I find Summarize Within results to be confusing and frustrating as well. Haven't been able to find out the reason for using a weighted summary. I did find info on how the weights are calculated, even though it applies to the tool from the GeoAnalytics standpoint, I think it still applies here.

BUG-000122455 for ArcGIS Pro

Summarize Within—Portal for ArcGIS | Documentation for ArcGIS Enterprise