[GRASS-user] flip raster

[Nikos Alexandris]

On Wed, 2008-10-08 at 23:48 -0300, José María Michia wrote:
> 2008/10/8 Nikos Alexandris <nikos.alexandris at felis.uni-freiburg.de>:
> > On Tue, 2008-10-07 at 01:37 +0100, Glynn Clements wrote:
> >> José María Michia wrote:
> >>
> >> > I've imported a NetCDF file (ETOPO1 model). The resulted raster appears
> >> > flipped vertically. How can I fix this? I try with mapcalc, without success:
> >> >
> >> > - neighborhood modifier: not accept computations in offset parameter, like
> >> > map[0,total_rows-row()]
> >> > - I dont know how to query map in arbitrary coordinates, like
> >> > map(x(),-1*y())
> >>
> >> There isn't any mechanism in r.mapcalc to achieve this. I'm not sure
> >> that it's possible to do it entirely within GRASS. Flipping
> >> geo-referenced data doesn't really make much sense.
> >>
> >> Either figure out how to import it with the correct orientation, or
> >> export it, flip the exported data, then re-import.
> >
> > Glynn and All,
> >
> > excuse me for hijacking the post. I am looking for a way (just for the
> > fun of the game or for philosophical re-search) to rotate geotiffs at
> > 180 degrees (i.e. flip vertically and horizontally). I've posted about
> > this in the gdal-dev list [1].
> >
> > Is there a way to accomplish a 180 deg. rotation using the
> > listgeo/geotifcp command line tools?
> 
> I'm not sure, but maybe this can be useful:
> 
> Alexander Schulze suggested me that I use the library to invest CDO latitudes:
> 
> http://www.mpimet.mpg.de/fileadmin/software/cdo/
> 
> Something like:
> 
> cdo invertlat filein fileout1
> cdo invertlon fileout1 fileout2
> 
> If you can use netCDF format, look at this:
> 
> http://nco.wiki.sourceforge.net/reverse a dimension
> 
> Saludos
> José María
> 
> > Thank you, Nikos
> >
> > [1] http://lists.osgeo.org/pipermail/gdal-dev/2008-October/018548.html

Hola Jose!

Thank you for your suggestion. I had a look but I am looking for a
simpler solution for this and I want to stick with (geo-)tiff files.
Hamish's method works great!

Regards, Nikos