R help - Nov 2010 - how to find near neighbors?

I am looking for an efficient way to find near neighbors...

More specifically...
I have two sets of points: A & B and I want to find
points in set B which are closer to set A than some
cutoff (or n-closest)

I will appreciate very much any pointers...

Ryszard

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Confidentiality Notice: This message is private and may ...{{dropped:11}}

Have a look at nncross() from the spatstat package.

Best regards,

Thierry

------------------------------------------------------------------------
----
ir. Thierry Onkelinx
Instituut voor natuur- en bosonderzoek
team Biometrie & Kwaliteitszorg
Gaverstraat 4
9500 Geraardsbergen
Belgium

Research Institute for Nature and Forest
team Biometrics & Quality Assurance
Gaverstraat 4
9500 Geraardsbergen
Belgium

tel. + 32 54/436 185
Thierry.Onkelinx at inbo.be
www.inbo.be

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than asking him to perform a post-mortem examination: he may be able to
say what the experiment died of.
~ Sir Ronald Aylmer Fisher

The plural of anecdote is not data.
~ Roger Brinner

The combination of some data and an aching desire for an answer does not
ensure that a reasonable answer can be extracted from a given body of
data.
~ John Tukey
  
> -----Oorspronkelijk bericht-----
> Van: r-help-bounces at r-project.org 
> [mailto:r-help-bounces at r-project.org] Namens Czerminski, Ryszard
> Verzonden: donderdag 18 november 2010 17:10
> Aan: r-help at r-project.org
> Onderwerp: [R] how to find near neighbors?
> 
> I am looking for an efficient way to find near neighbors...
> 
> More specifically...
> I have two sets of points: A & B and I want to find points in 
> set B which are closer to set A than some cutoff (or n-closest)
> 
> I will appreciate very much any pointers...
> 
> Ryszard
> 
> --------------------------------------------------------------
> ------------
> Confidentiality Notice: This message is private and may 
> ...{{dropped:11}}
> 
> ______________________________________________
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> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide 
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

Czerminski, Ryszard <Ryszard.Czerminski <at> astrazeneca.com>
writes:
> 
> I am looking for an efficient way to find near neighbors...
> 
> More specifically...
> I have two sets of points: A & B and I want to find
> points in set B which are closer to set A than some
> cutoff (or n-closest)
> 
> I will appreciate very much any pointers...
> 
> Ryszard
> 
'nn' in the RANN package represents a good solution for this task as it 
implements a very fast algorithm and provides the ability to search for 
nearest neighbors only within a certain radius.

Hans Werner