Message-ID: <200306301828.44882.baliola@riseup.net>
Date: 2003-06-30T19:12:30Z
From: Martin Wegmann
Subject: spatial correlation test
In-Reply-To: <3F0055E5.7010300@lancaster.ac.uk>
On Monday 30 June 2003 15:23, Barry Rowlingson wrote:
> Think you may be looking at the wrong sort of spatial correlation! For
> Geary tests you are comparing 'adjacent' objects, where adjacency is
> defined however you want - N-nearest neighbours, shared border between
> regions etc etc.
sorry, I misunderstood the purpose of geary's I test, thanks for this info.
> When you say 'sampled data' it sounds more like you've got samples
> taken at locations, and you want to investigate spatial correlation as a
> function of distance between samples? Am I guessing right?
Yes you are right. I want to look for spatial correlation of my samples as a
function of distances between sampling sites (x,y coords).
> Take a look at some of the R kriging libraries, which will have
> functions to plot variograms. This is a plot of something like
> E(|Y_i - Y_j|) against distance.
>
> Baz
I found variograms() and correlograms(), but is there a way to get the a
p-value for spatial correlation?
additionaly I found sp.correlogram() but again with this mysterious "nb
class".
thanks, martin