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Select polygons

3 messages · Morten Sickel, Edzer Pebesma

#
I am reading in a shape file using read.shape() I would like to select some of the polygons in the shape file, depending on data in the att.data ... but for some (probably simple) reason, it doesn't work.

having read the shape file into the object nw, I would believe that

nw2=nw[nw$att.data$FTEMA>0,]

would select those polygons with FTEMA>0 but it give sme the error "incorrect number of dimentions" removing the last , I think I get the selection I wants, but what it returns is no longer a map object...

Any clues anywhere?

--
Morten Sickel
Norwegian Radiation Protection Authority
tel (+47) 6716 2551
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The "new style" way of doing this, using the classes of package sp, 
would be reading the shape with readOGR (in package rgdal), and then 
selecting by

nw2 = nw[nw$FTEMA>0, ]
--
Edzer
Morten Sickel wrote:

  
    
#
Great! Thanks, that did it!

Morten

-----Original Message-----
From: Edzer Pebesma [mailto:edzer.pebesma at uni-muenster.de]
Sent: Friday, July 04, 2008 4:51 PM
To: Morten Sickel
Cc: r-sig-geo at stat.math.ethz.ch
Subject: Re: [R-sig-Geo] Select polygons

The "new style" way of doing this, using the classes of package sp, would be reading the shape with readOGR (in package rgdal), and then selecting by

nw2 = nw[nw$FTEMA>0, ]
--
Edzer
Morten Sickel wrote: