I've read the other similar stack questions and they weren't helpful, as in the processes didn't work or there was some ambiguous field references that may have contributed to my confusion and error.

I am using ArcGIS Pro.

I have about 199 polygons for parcels within a single shape file. There are 4000 or so polygons representing slope sections in a different shapefile I have in a layer drawn above the parcels. I need to connect the two somehow in a way that lets me calculate summary statistics to identify the total percentage of each parcel that is comprised of slopes.

I tried this tutorial via the comment that explains method for vector, and I don't know where I went wrong. I wasn't sure what it meant by zone so I used parcelID

  1. Union slope shapefile to parcels shapefile

  2. Calculate summary statistics according to the above tutorial. But summary stas came out blank.

  3. What would I do after that to take that calculation and "cut it down" to the percentage per actual parcel area? My understanding is that the problem with the union of parcels and slope shapefiles is that the parcels are "expanded" to include the shape of the slope polygons that overlap or intersect rather than only those entirely within their parcel boundaries.

A GIS colleague mentioned something about using dissolve - I think he meant dissolve the slopes polygons to get them in larger polygons and then union those with the overall slopes shapefile to the parcels shapefile, but I think that still does not solve my problem with getting the "expanded (unioned) parcel-slope polygons" back to the scale of the original parcel sizes/boundaries and the slope summary stats as a percentage of each original parcel size.

  • It sounds like Union followed by Summary Statistics should work so I think you should overhaul your question to describe precisely what parameter values you used with each when it appeared not to work for you.
    – PolyGeo
    Commented Jun 2, 2022 at 7:45
  • Intersect them and do pivot table in Excel with parcel fid as rows header, slope categories as columns, area is one to summarize.
    – FelixIP
    Commented Jun 2, 2022 at 9:41


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