topic Re: Intersection of layers: how is output defined? in ArcGIS Online Questions

Intersection of layers: how is output defined?

Mikhail — Tue, 11 Jan 2022 05:10:54 GMT

Hi, I have two layers, the first is composed of polygons representing the districts, and the second is a large polygon showing the area with a specific soil type. I intersect the two layers to see which districts have this soil type, and have a problem with the polygons on the border. Ideally, I'd like to see which share of their area has this soil, but the output of analysis is a bit confusing. I get two variables, the first is the Shape__Area which is the total area of a polygon in question, not the part contained in the soil polygon. The second is the Area in sq kilometres. I wonder if it is the area of the intersection, or again the total polygon, now in different units. Could you help?

Re: Intersection of layers: how is output defined?

AmandaRing — Thu, 13 Jan 2022 15:23:49 GMT

Hi @Mikhail,
The 'Area in Sq. Kilometres' field is the one that is generated by the Overlay analysis tool, and it will contain the calculated area of the intersection of the two polygons.
The units of this field will be calculated either in Square Miles or Square Kilometers, depending on the Units setting in your profile.

As you observed, the 'Shape_Area' field is an artifact from the first input polygon feature. The 'Shape_Area' and 'Shape_Length' fields are virtual ArcGIS system fields whose accuracy is not maintained if the data or the spatial reference changes. Therefore, these fields should NOT be used in analyzing your results.

Re: Intersection of layers: how is output defined?

Mikhail — Wed, 19 Jan 2022 06:21:30 GMT

Hi Amanda, thank you, I'll use the 'Area in Sq. Kilometres' field.