[R] R and DBSCAN

[Paco Pastor]

Hello everyone,

When looking for information about clustering of spatial data in R I was 
directed towards DBSCAN. I've read some docs about it and theb new 
questions have arisen.

DBSCAN requires some parameters, one of them is "distance". As my data 
are three dimensional, longitude, latitude and temperature, which 
"distance" should I use? which dimension is related to that distance? I 
suposse it should be temperature. How do I find such minimum distance 
with R?

Another parameter is the minimum number of points neded to form a 
cluster. Is there any method to find that number? Unfortunately I 
haven't found.

Searching thorugh Google I could not find an R example for using dbscan 
in a dataset similar to mine, do you know any website with such kind of 
examples? So I can read and try to adapt to my case.

The last question is that my first R attempt with DBSCAN (without a 
proper answer to the prior questions) resulted in a memory problem. R 
says it can not allocate vector. I start with a 4 km spaced grid with 
779191 points that ends in approximately 300000 rows x 3 columns 
(latitude, longitude and temperature) when removing not valid SST 
points. Any hint to address this memory problem. Does it depend on my 
computer or in DBSCAN itself?

Thanks for the patience to read a long and probably boring message and 
for your help.

-- 
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Francisco Pastor
Meteorology department, Instituto Universitario CEAM-UMH
http://www.ceam.es
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mail: paco en ceam.es
skype: paco.pastor.guzman
Researcher ID: http://www.researcherid.com/rid/B-8331-2008
Cosis profile: http://www.cosis.net/profile/francisco.pastor
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46980 PATERNA (Valencia), Spain
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