My starting point is a series of bounding box polygons, representing the extents of all the data sets in my inventory.

I am trying to produce an output grid showing the frequency of coverage over the the extent of the entire inventory, in my case the world.

I had thought that a combination of Intersect and Dissolve functions would get me what I wanted, but haven't had any success with this approach yet.

Can anyone suggest a better process? I am open to any suggestions, whether it be some tools already available in ArcMap, QGIS...etc or through programmatic/scripting using ArcPy,GDAL...etc.

  • Can you describe in more detail what the output grid should be? When I think grid, I think of a raster, but maybe you are thinking of something else. – blah238 Apr 25 '12 at 5:51

One simple way to do this would be to create a fishnet polygon layer using Create Fishnet from the same extents as your bounding box layer, and divide it into an appropriate number of columns/rows.

Then perform a Spatial Join with the target layer being the fishnet polygons and the join layer being your bounding box polygons. Do a one to one join; this creates a JOIN_COUNT field with the number of bounding box features that intersect each fishnet polygon.

Symbolize the output by JOIN_COUNT and you have a quick and dirty heat map:

Fishnet Heat Map

  • 1
    This is exactly what I was looking for. Thank you. – user890 Apr 25 '12 at 11:13

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.