R help - Nov 2008 - making shape files into data bases usable within maps

Hello R-helpers,

a while ago I had a question about identifying points on a map
belonging to a specific region.
I learned at that time that if the region is part of one of the
databases in the library maps that is easily done by using the
function map.where()  -- thanks to Duncan Murdoch for the hint!

My now related question is, what if my geographical information is not
already available within maps (the library) but is in a shape file? I
can read the file in R, but I'm not clear how to make it into a
database that is "understood" by the functions in the library maps. Is
this at all possible?

Thank you very much -- once again -- in advance

claudia

-- 
Claudia Tebaldi
Research Scientist, Climate Central
http://www.climatecentral.org
currently visiting IMAGe/NCAR
PO Box 3000
Boulder, CO 80305
tel. 303.497.2487