[R] nearest neighbour
r.turner at auckland.ac.nz
Wed Apr 16 03:04:57 CEST 2014
Please keep communications on-list unless there is a genuine reason not to.
To answer your question: Yes, you need to convert to ppp format; the
nnwhich() function requires its first argument to be of class "ppp".
My example showed you how to construct or "estimate" a window if you
don't have or know the window a priori.
On 16/04/14 01:23, Monaly Mistry wrote:
> Hi Rolf,
> Thank you very much, I just have one other question, do I need to
> change the data frame into ppp format? I've tried using as.ppp but get
> the following error message:
> Error: x,y coords given but no window specified
> On Thu, Apr 3, 2014 at 9:23 PM, Rolf Turner <r.turner at auckland.ac.nz
> <mailto:r.turner at auckland.ac.nz>> wrote:
> On 04/04/14 01:16, Monaly Mistry wrote:
> If I have a data frame of the location of individuals (x and y
> how do I find the 5 nearest neighbours for each individual.
> The nnwhich() function from the spatstat package will do this for you.
> require(spatstat) # You need to have *installed* spatstat!
> W <- ripras(ddd) # Where "ddd" is the name of your data frame.
> X <- ppp(x=ddd[,1],y=ddd[,2],window=W)
> n5 <- nnwhich(X,k=1:5)
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