cluster analysis

ish at alla.pl.swf.usace.army.mil ish at alla.pl.swf.usace.army.mil
Wed Mar 12 13:40:53 EST 1997


>Is there a grass program for running a cluster analysis
>of sites or raster cells?
>I couldn't find any obvious reference in g.manual or g.help.

Not directly, but there are ways to dump the values of raster maps
at the site coordinate locations into ascii files. In the s.menu
module there is an option for generating a "sites report" for output
to a format readable by S (the precusor to S-Plus Stat package.
Other GRASS users have been able to link GRASS output to Splus
somewhat more dynamically.

The sites report is a file of the values of other raster maps at
each site location plus some other information about the ranges
of values of your raster maps. If you're not going to employ S-Plus
it might be easier to obtain values of raster maps at point locations
for input to stat packages is using the command r.what with the site
coordinates piped from a file. Hope this helps.

Ishmael Williams
US Army Corps of Engineers
Fort Worth District



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