[R-sig-Geo] "clustered" Random distribution of statial points

[Roland Kaiser]

You may also want to try the Thomas process

ow <- map('state','illinois', plot=FALSE, fill=TRUE)
ow.sppgs <- map2SpatialPolygons(ow, IDs=ow$names,
	proj4string=CRS("+proj=longlat"))
ow <- as(ow.sppgs, "owin")
x <- rThomas(2, 0.1, 10, win = ow)
sp.pts <- as(x, "SpatialPoints")
plot(ow.sppgs)
points(sp.pts)

Roland

> Dear Quentin,
>
> Have a look at the spatstat package. The Strauss process or hard- 
> core process is what you are looking for.
>
> HTH,
>
> Thierry
>
>
> ---------------------------------------------------------------------- 
> ------
> ir. Thierry Onkelinx
> Instituut voor natuur- en bosonderzoek / Research Institute for  
> Nature and Forest
> Cel biometrie, methodologie en kwaliteitszorg / Section biometrics,  
> methodology and quality assurance
> Gaverstraat 4
> 9500 Geraardsbergen
> Belgium
> tel. + 32 54/436 185
> Thierry.Onkelinx at inbo.be
> www.inbo.be
>
> To call in the statistician after the experiment is done may be no  
> more 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-sig-geo-bounces at stat.math.ethz.ch [mailto:r-sig-geo- 
> bounces at stat.math.ethz.ch] Namens Quentin LEMOULAND
> Verzonden: woensdag 11 maart 2009 16:57
> Aan: r-sig-geo at stat.math.ethz.ch
> Onderwerp: [R-sig-Geo] "clustered" Random distribution of statial  
> points
>
> Hello,
>
> I am trying to make a "clustered" Random distribution of statial  
> points.
> I want to make p "random" distribution of n points.
> But I don't want a typical random distribution. I want a clustered  
> one (with minimal distances bettween my points fixed as my observed  
> distribution: c(3.9,3.3,1.4,1.4,0.7,0.7)).
> I have seen that the spsample function from package sp could "in  
> theory" make this...
> But impossible to understand how to make it work:
>
>> spsample(var,10,"clustered")
> Erreur dans `[<-.data.frame`(`*tmp*`, , j, value = c 
> (-33.8558590595841, -24.8671595071446,  :
>   replacement has 14 rows, data has 12
>
> Does anyone know the solution, there is no example in the help page  
> of spsample.
>
> Thanks by advance,
>
> Quentin
>
>
>
>
>
>
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