Nikolas,
reprojection from rotated pole to lat/lon will give you two
two-dimensional coordinate variables, traditionally called lat and lon.
First create these.
- Create a ucar.unidata.geoloc.projection.RotatedPole with the
projection parameters.
- For each point in the two-dimensional grid, create a
ucar.unidata.geoloc.ProjectionPointImpl containing the rotated
coordinates and an empty ucar.unidata.geoloc.LatLonPointImpl to store
the results.
- Use Projection.projToLatLon (that is, RotatedPole.projToLatLon) to
calculate the lat/lon coordinates, and store them in your new coordinate
variables.
See testProjToLatLon in this unit test:
https://github.com/Unidata/thredds/blob/master/cdm/src/test/java/ucar/unidata/geoloc/projection/RotatedLatLonTest.java
Kind regards,
Ben.
On 21/07/16 02:25, Dahn, Nikolas wrote:
Hello!
I'm developing an application module which should import a GRIB(2) file, select
a subset of the variables and save them to a NetCDF file.
My problem is that some of the variables use rotated lat/lon. They seem to be correctly encoded
(i.e. the dimensions have the standard_name "grid_latitude"/"grid_longitude"
set and there's a reference variable with grid_mapping_name, grid_north_pole_latitude and
-longitude set correctly), but I have to convert them to regular lat/lon and I don't know how.
My question now is: given a Variable object with Dimension i,j in rotated
lat/lon, what do I have to do to convert it to regular lat/lon? At this point
in the program I don't care about the actual values.
Thanks in advance!
Nikolas
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