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I have a geodatabase with a given number of polygon features. I would like to generate a layer (V) that displays the number of overlapping polygons at any given (x,y) location spanned by my polygons. For example, if at (x1,y1) I have two overlapping polygons my V(x1,y1)=2, if I have no polygons at (x2,y2) then V(x2,y2)=0, and so on. What is the easiest way to build this map? I am currently reviewing join and merge tools to see how I can make this work.

PolyGeo
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val
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3 Answers3

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I would loop over each polygon and first create a binary raster where the cell value is one inside the polygon, and zero outside, and then use map algebra to add it to a total raster.

Unless you have a trivial number of polygons, you will probably want to write an arcpy script to do this.

Regan Sarwas
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  • there must be an easier way using already built in tools? another post http://gis.stackexchange.com/questions/51929/how-to-count-and-rasterize-polygon-overlaps-in-arcgis-desktop describes this but the dissolve function is not adding up the overlapping polygons. – val Nov 08 '14 at 01:16
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I know this is an older post but I had a similar problem and found this tool http://www.arcgis.com/home/item.html?id=1dd4a6832b3d40b494dbf8521cc5134c, was the easiest solution.

PolyGeo
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Nicholas Rubin
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using union and dissolve i was able to get it to work, the key for me was to select the right Dissolve_Field to Count over in the Statistics Field (i.e. both fields match and I used "shape_Area" as the unique indentifier). Thanks for the comments! This post was most helpful for me: Counting and rasterizing polygon overlaps in ArcGIS Desktop?

Community
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val
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