Proj4 natgrid coordinate transformation error
On Mon, 24 Mar 2014, Jonas Schmedtmann wrote:
Hi everyone, I?m trying to use the nadgird parameter for coordinate transformation from the portuguese Hayford Gauss IGeoE system to UTM 29 WGS84 used in Landsat images for Portugal. I have the following code, which produces an error, so I wonder if I got everything right in my proj4strings. I?ve tried a lot of things, and an intensive google search did not solve my problem either. I got the file 'ptLX_e89.gsb? from a professor of mine so I assume there?s nothing wrong with it.
The error message says: failed to load datum shift file, suggesting that
it isn't where it should be.
You didn't report your output from sessionInfo(), not the messages printed
when rgdal is loaded. The resolution is system-dependent, but at base the
file must be where PROJ expects to find it. If your rgdal is the CRAN
Windows oe OSX binary, the directory should be system.file("proj", package
= "rgdal")[1]; if PROJ is provided externally, where the share/proj
directory is (default /usr/local/share/proj for source installs).
Roger
PROJ4_IGEOE<-CRS("+proj=tmerc +lat_0=39.66666666666666 +lon_0=-8.131906111111112 +k=1 +x_0=200000 +y_0=300000 +ellps=intl +units=m +nadgrids=ptLX_e89.gsb +wktext +no_defs")
PROJ4_UTM<-CRS("+proj=utm +zone=29 +ellps=WGS84 +datum=WGS84 +units=m")
area<-readShapePoly("../01 Dados/02 Dados espaciais/AREA_ESTUDO", proj4string=PROJ4_IGEOE)
area_wgs84<-spTransform(area, PROJ4_UTM)
Error in .spTransform_Polygon(input[[i]], to_args = to_args, from_args = from_args, : error in pj_transform: failed to load datum shift file
I?d appreciate any help. Thanks in advance! Jonas Schmedtmann
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Roger Bivand Department of Economics, Norwegian School of Economics, Helleveien 30, N-5045 Bergen, Norway. voice: +47 55 95 93 55; fax +47 55 95 91 00 e-mail: Roger.Bivand at nhh.no