[R] spatial correlation test

Martin Wegmann baliola at riseup.net
Mon Jun 30 21:12:30 CEST 2003


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




More information about the R-help mailing list