Hi Don,
this is not a problem in the grid definition, but a problem of the code. This is not just a problem in your Java code, but also in the Fortran code that is used in regional climate models (and the output files in the link you provided are from the Danish regional climate model). It may well be that the Java version was derived from the Fortran version.
This strange thing happens, when the geographic pole and the rotated pole are the same or the rotation is just along the equator. In your case you may either set grid_north_pole_longitude=180. before entering your Java routine or just ignore the rotated pole at all since in this special case it is rlon = geographical longitude and rlat = geographical latitude.
Regards
Burkhardt
Am 24.04.2012 um 18:50 schrieb Don Murray:
> Hi-
>
> I have some climate files that have a rotated-pole projection defined as:
>
> char rotated_pole ;
> rotated_pole:grid_mapping_name = "rotated_latitude_longitude" ;
> rotated_pole:grid_north_pole_latitude = 90.f ;
> rotated_pole:grid_north_pole_longitude = 0.f ;
>
> When I read this through the netCDF-Java library, the data end up 180 degrees off from where it is supposed to be (African data is over Hawaii). I talked to John Caron at Unidata and he doesn't know if it is a problem with the grid definition or the rotated-pole code in netCDF-Java.
>
> Does anyone on this list have a pointer to the equations for the rotated pole and or know if there anything wrong with the grid mapping definition? Should the above imply a unity transformation?
>
> Sample files are at:
>
> http://dods-testbed.ictp.it/aap/ENSEMBLES_AMMA/ERAIN/Daily/
>
> thanks for the help!
>
> Don
> --
> Don Murray
> NOAA/ESRL/PSD and CIRES
> 303-497-3596
> http://www.esrl.noaa.gov/psd/people/don.murray/
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Received on Tue Apr 24 2012 - 13:11:17 BST
