[R] nndist R vs. ArcGIS
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.
> 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.
More information about the R-help