[R-sig-Geo] writeRaster - netcdf - Rotation

[Philipp Reiter]

Hi Robert and Pascal,
 
thanks for the tips, but my problem isn't completely solved. The explicit laebling of x and y works, but doesn't change the rotation.
I followed Pascals hint:
My raster*-Object has the dimensons: "220 171 x".
When I export this raster*-Obejct as posted below as nc-file and reimport it with the ncdf-Package, the dimensions are: "171 220 x". The explicit labeling doesn't change that. The first dimension is always 171 in the nc-file, no matter if its names 'easting' or 'northing'. To me it looks like raster and ncdf interpret x and y differently?!
 
Beste regards
Philipp
 
 
Philipp,

You are right, the labels easting and northing are reversed. I will fix
that. You can set them yourself as illustrated below:

library(raster)
tmp<- raster(nr=5, nc=10,crs='+proj=utm +zone=12')
tmp[] <- 1:ncell(tmp)
writeRaster(tmp, filename='export.nc', format="CDF", overwrite=TRUE,
xname='easting', yname='northing')
raster('export.nc')

nc <- open.ncdf("export.nc")
get.var.ncdf(nc,"easting")

Robert

On Fri, Mar 22, 2013 at 7:17 AM, <amock at gmx.li> wrote:

>
>  Hey there,
> I’ve got a problem concerning exporting a raster*-Object as nc-File:
> When exporting rasterLayers or rasterBricks as nc-Files with writeRaster
> from the raster-Package, easting and northing in the resulting nc-File are
> switched, which results in a rotated plot. I can correct this afterwards,
> but it should be possible to be correct right away?!
>
> Example code for a rasterLayer:
> tmp <- raster(readGDAL(‘example.asc’,p4s="+init=epsg:31467"))
> writeRaster(tmp, filename=’export.nc’, format="CDF", overwrite=TRUE)
> nc <- open.ncdf("export.nc")
> x <- get.var.ncdf(nc,”easting”)
> y <- get.var.ncdf(nc,”northing”)
>
> R version 2.15.3 (2013-03-01)
> Platform: x86_64-w64-mingw32/x64 (64-bit)
> ncdf_1.6.6    raster_2.1-16 rgdal_0.8-5   sp_1.0-6
>
> I hope someone can give me a hint! Thanks in advance!
> Philipp
>
>
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