[R-sig-Geo] CRS parameters

[Roger Bivand]

On Fri, 1 Sep 2006, Laurent Dubroca wrote:

> Hello list,
> 
> I use spmaps 0.1-4+gdal 1.3.1+proj 4.4.9 with R 2.3.1.
> Starting with the example of the spmaps package and the 
> map2SpatialPolygons function, it seems that the proj4strings parameters 
> of this line are not correct :
> 
> nor_coast_poly_sp <- map2SpatialPolygons(nor_coast_poly, IDs=IDs, 
> proj4string=CRS("+proj=longlat +datum=wgs84"))
> 
> The message returned is
> 
> "Erreur dans CRS("+proj=longlat +datum=wgs84") :
>          unknown elliptical parameter name"

You are running with rgdal loaded. I get the same error, because the datum
should be WGS84 rather than wgs84, see proj -le. I'll correct the example.

> 
> With the proj -l command I cannot find the projection called "latlong".
> 

No, that's OK, the longlat and latlong are placeholders for unprojected 
data - we use longlat because the X coordinates are the first column, not 
the second.

Thanks for a helpful report.

Roger

> What's wrong ? Does my installed version of gdal or proj aren't correct ?
> 
> Laurent
> 
> 
> 
> 
> 
> 

-- 
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.Bivand at nhh.no