[R] Spatial Autocorrelation for point data

[Roger Bivand]

On Mon, 26 Apr 2004, Jan Verbesselt wrote:

> Hi R helpers,
> 
> Is there a function (package?) in R available which tests "spatial
> autocorrelation" between points (e.g. vector layer of weather stations)?
> (e.g. Moran's I...)
> 
> Via the archives we found out that there is a package 'spdep' which uses
> grid data for testing spatial autocorrelation.
> 

I think you will find that spdep contains the tools you need to build 
neighbour lists from points (for example by triangulation, tri2nb()), in 
order to calculate Moran's I. Look at the help pages for knearneigh(), 
tri2nb(), dnearneigh(), and/or graph2nb() to get an idea of the 
possibilities. Other functions can be used to modify triangulation 
neighbours, bu note that if you generate points with no neighbours for 
your definition of neighbours, you will need to specify this in arguments 
to analysis functions. 

Roger Bivand

> Thanks a lot,
> Jan
> 
> 
> _______________________________________________________________________
> Jan Verbesselt 
> Research Associate 
> Lab of Geomatics and Forest Engineering K.U. Leuven
> Vital Decosterstraat 102. B-3000 Leuven Belgium 
> Tel:+32-16-329750   Fax: +32-16-329760
> http://gloveg.kuleuven.ac.be/
> 
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-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand at nhh.no