[R] Help with saptial analysis (cluster)

Roger Bivand Roger.Bivand at nhh.no
Fri Apr 27 13:05:40 CEST 2007


ONKELINX, Thierry <Thierry.ONKELINX <at> inbo.be> writes:

> 
> Dear Fransico,
> 
> The distance matrix would be 102000 x 102000. So it would contain 10404000000 
values. If you need one bit for
> each value, this would requier 9,7 GB. So the distance matrix won't fit in 
the RAM of your computer.

Perhaps you could make progress by using a 2D kernel density - there are 
functions among others in the MASS and splancs packages, or by binning - 
Bioconductor's hexbin package comes to mind. Then you would be looking for 
areas of increased density on the grid (in points per unit area or equivalently 
counts per bin) rather than at the interpoint distances. The kernel2d() 
function in splancs handles a data set of your size with no problems.

Roger

(with apologies for pruning, gmane is very dictatorial)

> 
> Cheers,
> 
> Thierry
>



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