Re: [R] nndist R vs. ArcGIS

From: <Seeliger.Curt_at_epamail.epa.gov>
Date: Mon, 11 Apr 2011 11:54:50 -0700

Alexis wrote:
> Can anyone tell me why I would get different average nearest neighbor
values
> for the same set of coordinates between ArcGIS 10 and R? Sometimes the
> difference in distance is over 1.3 km.

spatstat::nndist calculates Euclidean distances rather than distances along the earth's surface, which is probably what you're getting from AG. A very short example illustrating the problem would be helpful in determining if I'm at all right; on the other hand I'm glad you're testing your results.

You might peek at the current thread "Geographic distance between lat-long points in R" for more information.

cur

-- 
Curt Seeliger, Data Ranger
Raytheon Information Services - Contractor to ORD
seeliger.curt_at_epa.gov
541/754-4638

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