[R] mclust - clustering by spatial patterns

Tony Plate tplate at blackmesacapital.com
Fri Dec 19 01:33:54 CET 2003


You could just convert your binary spatial data to numeric 0/1 or -1/1 and 
give it to Mclust.  That would violate the assumptions of the Gaussian 
model in Mclust, so you should be very careful about interpreting the 
results.  However, if the results are at least as "interesting" as those 
you get from a non-model-based hierarchical clustering run, then that could 
be an indication that the approach has merit, and then you could 
investigate how to build a model-based clustering algorithm that is 
appropriate for your data.  (I don't think it would be that hard to write 
down some equations giving the probability of each presence matrix being 
generated for each component of the mixture model, but I don't know how 
hard it would be implement the EM search for an appropriate mixture model.)

-- Tony Plate

At Thursday 08:55 PM 12/18/2003 +0000, Jarrod Hadfield wrote:
>Dear All,
>
>I have spatial data (presence/absence for 4000 squares) on 250 bird 
>species and would like to use a model-based clustering technique to test 
>for species associations.  Is there any way of passing a 
>distance/correlation matrix to mclust as with hclust, rather than the 
>actual data?  Or alternatively, is there a way of getting mclust to handle 
>binary data?
>
>I'd appreciate any suggestions!
>
>Cheers,
>
>Jarrod
>
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