[R] nndist R vs. ArcGIS

Rolf Turner rolf.turner at xtra.co.nz
Tue Apr 12 02:40:17 CEST 2011

On 12/04/11 07:32, Barry Rowlingson wrote:
> On Mon, Apr 11, 2011 at 4:49 PM, smoluka<smoluka at geo.oregonstate.edu>  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.
>   Edge correction? In a spatial point pattern, points near the boundary
> of your window are less likely to have a near neighbour because only
> some of the surrounding space can possibly have points. I think
> functions in spatstat will correct for this.
         No.  Not as far as I am aware or can discern.  The function
         nndist() does ***not*** invoke any edge correction.  It simply
         calculates the distances as they are, for the points that appear
         in the window, and takes the appropriate minima.


                 Rolf Turner
> Make a simple test example and tell us what functions you are using.
> And also try the r-sig-geo mailing list  for this sort of thing.
> Barry

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