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I'm trying to find the shortest edge-to-edge distance between polygons in a layer. An example is a table of the distances from county to county in a state. I'm attempting to use the generate near table tool. I set the proximity to 0 and made sure to de-select only the nearest neighbor. It runs for a few hrs, but when its finished, the ouput only returns the distance of the 1 nearest neighbor, which is 0 because they are touching each other. Any help would be much appreciated!

-Kevin

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You're basically trying to get distance from a county to all other county in a state right? So why set the max distance to 0? –  gotchula Jan 6 '11 at 23:06
    
I may have misinterpreted the near table instructions, but I thought an entry of the default 0 set the radius to all features in the layer. I'm crossing my fingers and rerunning the tool setting the radius to a large number –  Kevin Jan 10 '11 at 19:50
    
So, I was able to get a table of numbers, but they are not in the right units. Does anyone know what the standard units are for the distance output? –  Kevin Jan 11 '11 at 19:03
    
from the docs: "The distances calculated by Near are determined by the units of the Input Features. If the linear units of the input feature class are in Meters, the Search Radius will default to Meters. The units of the Search Radius can be changed. Specifying one kilometer is the same as entering one thousand meters. However, the value for the NEAR_DIST will be based on the units of the input." –  scw Feb 16 '11 at 5:33
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1 Answer

The Near calculations in my experience are only based on the vertices of the polygon, so I found that as long as you made sure not to select only closest in the dialog box and selected a number for the total number, in your case the number of counties - 1 then it should work fine. I did my test on cadastral parcels and set this number to 50, and the near table generated gave me the top 50 closest polygons.

Now as I said this is going to be vertex to vertex as this is the way the tool works. Another option to achieve the edge scenario is to generate a centroid feature class of the counties and then do your near calculations on this and then verify the results from the vertex table generated in the above method.

Hope this helps, CDB

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