awiseman

Summing nearby points?

Discussion created by awiseman on Feb 22, 2011
Latest reply on Feb 22, 2011 by awiseman
I have a problem I can't get my head around. I have a shapefile of points (project locations) and I want to merge/join/group nearby ones and add up their attributes in order to show where we've done multiple projects in the same area. Say if there are two points within 50 meters of each other, one for $100 and one for $50, I add them up and get a result that says 2 in that area for $150.

Sort of like how web maps do them -- Ushahidi for example, when you're zoomed out it merges points together and gives you the number of projects in that area: http://haiti.ushahidi.com/  I wouldn't need to be able to disaggregate as I zoom in though.

Basically at the end I want to be able to show where we've done multiple projects in the same area - say a total of 50 places we've done 2 projects, 17 places we've done 3, 8 we've done 4 etc. Ideally I'd be able to show that on a map as well.

I've tried creating a buffer and doing a union, but can't see how to add the attributes.

Thanks!

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