On Thu, 9 Jul 2009, Barry Rowlingson wrote:
On Thu, Jul 9, 2009 at 9:23 PM, Paul Hiemstra<p.hiems...@geo.uu.nl> wrote:
Hi,
More in general you need to take a look at the sp-pacakge for Spatial
classes in R. Once your data is in these classes you can use spTransform
from the rgdal pacakge to perform the projection. spTransform uses the proj4
library. You need to find the so called proj4 strings describing both the
source and target projection.
There seems to be several ways of reprojecting/coordinate transforming in R...
package:sp, in ?is.projected, mentions an spproj package which I
can't find. Is that just a documentation error?...
Documentation error, will be corrected.
package:rgdal has spTransform as mentioned...
Correct, a good deal based on your work for vector data and projection.
package:proj4 seems to be an independent interface to the PROJ4 library.
Odd and unhelpful, a one-off attempt to replace mapproj, which works
together with the maps package, but has unclear license conditions. This
package doesn't interface with any other spatial packages, and the author
has never replied to questions about coordinating to get rgdal on CRAN as
an OSX binary package. Use proj4 or maptools is you must, rgdal for
preference - spproj was a development vehicle for methods that are now in
rgdal.
Roger
Barry
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--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: roger.biv...@nhh.no
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