[GRASS-stats] Nearest neighbour distance distribution but between polygons

[G. Allegri]

In Grass maybe you could use the boundaries instead of the areas. The
distances would be between the boundaries' linestrings instead of centroids.

giovanni

2012/5/7 Roger Bivand <Roger.Bivand at nhh.no>

> On Mon, 7 May 2012, Rainer M Krug wrote:
>
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>> Hi
>>
>> I have the following (presumibly simple?) question:
>>
>> I have a certain number of patches (islands) in a landscape of which I
>> need to know the nearest neighbour distance. As the problem is related to
>> dispersal, I would need to know the actual shortest distance between the
>> actual polygons and not only the centroids. Is there an easy way to obtain
>> these in R or in GRASS? I am only aware of nearest neighbour distance
>> between points.
>>
>
> In R, if the coordinates are projected, use gDistance(..., byid=TRUE) in
> the rgeos package to get a matrix in the metric of the projection. If not
> projected, project if possible.
>
> I don't think that the geosphere package provides for the unprojected case.
>
> Roger
>
>
>
>> Thanks,
>>
>> Rainer
>>
>>
>> - --
>> Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation
>> Biology, UCT), Dipl. Phys.
>> (Germany)
>>
>> Centre of Excellence for Invasion Biology
>> Stellenbosch University
>> South Africa
>>
>> Tel :       +33 - (0)9 53 10 27 44
>> Cell:       +33 - (0)6 85 62 59 98
>> Fax :       +33 - (0)9 58 10 27 44
>>
>> Fax (D):    +49 - (0)3 21 21 25 22 44
>>
>> email:      Rainer at krugs.de
>>
>> Skype:      RMkrug
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>>
> --
> Roger Bivand
> Department of Economics, NHH Norwegian School of Economics,
> Helleveien 30, N-5045 Bergen, Norway.
> voice: +47 55 95 93 55; fax +47 55 95 95 43
> e-mail: Roger.Bivand at nhh.no
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