Shapefile Overlap as a Percentage

The spatial match tool intersect tool shows IF a shapefile overlays another. I want to calculate how much one shape overlays the other.

Here is my example:

I have 2 square shapefiles shown as 1 & 11. I want to calculate a percentage or area of each of these squares that overlap a circle (second picture). So my expectation is the value for square 1 is ~15% and square 2 is ~25%.

2 Squares.JPG

Spatial Analysis

Accepted answers

OllieClarke

Hi @cjmason105

If your Squares and Circles are in the same stream then @RolandSchubert has you covered, but if they're in different data streams, then you can use this approach:

In the Spatial Match tool you can output the intersection object if you're matching by intersection:

And you can make use of the spatial formulae to work out your percentage without needing 2 spatial info tools:

ST_Area([IntersectPoly],"SqKm")
/
ST_Area([Square],"SqKm")
*100

Hope that helps,

Ollie

Overlap.yxmd

All comments

RolandSchubert

Hi @cjmason105 ,

I think, the Spatial Process tool could be helpful. You can create a new spatial object for the overlap area. The Spatial Info tool returns the area of the overlap and the base object, calculation of percentage can be done using Formula tool.

What done you think?

Best,

Roland

Overlap.yxmd

OllieClarke

Hi @cjmason105

If your Squares and Circles are in the same stream then @RolandSchubert has you covered, but if they're in different data streams, then you can use this approach:

In the Spatial Match tool you can output the intersection object if you're matching by intersection:

And you can make use of the spatial formulae to work out your percentage without needing 2 spatial info tools:

ST_Area([IntersectPoly],"SqKm")
/
ST_Area([Square],"SqKm")
*100

Hope that helps,

Ollie

Overlap.yxmd

cjmason105

Ollie, I think your solution for 2 data streams is the best option for me.

Just to be clear, I want multiple boxes and multiple circles.

For each box, I want to know what circle it overlaps and the percentage. Am I understanding this correctly?

cjmason105

Roland, thank you so much for your answer. I think this is a great solution but I think Ollie's might be a better fit for my use case. I just asked for clarification on his.

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