Re: Import and reproject COSMO REA6 data set
Markus Metz <[email protected]>
| Newsgroups | gmane.comp.gis.grass.user |
|---|---|
| Message-ID | <CAG+h=FHrBQbieYA+OU+2EzC-vbcsyj0rPreGawTiCRyCH_EHCg@mail.gmail.com> |
On Mon, Nov 6, 2017 at 2:05 PM, Helmut Kudrnovsky <[email protected]> wrote: > > Pietro Zambelli wrote > > Dear Helmut, > > > > On 06/11/17 08:22, Helmut Kudrnovsky wrote: > >> not really an answer, but the data documentation says: > >> > >> "Output format: GRIB 1, rotated spherical" > >> > >> a quick web search shows some hints to handle such data. > > > > Looking at the reference model manual: > > > > http://www.cosmo-model.org/content/model/documentation/core/cosmoDyncsNumcs.pdf > > > > at page 25, there are some equation to transform the rotated spherical > > coordinates back and forward, see the attached image. > > > > Are these the hints that you mentioned in your previous reply? > > > > Should I convert the raster in to a x_s, y_s, z list of points and write > > a function to convert the spherical coordinates (x_s, y_s) values > > defining my own python script to apply the transformation function and > > generate the lat, lon, z triplet of values, to be imported into a WGS84 > > location? > > Any better approach/idea? > > > > Thank you for the support. > > never used such kind of data for myself; maybe it would be worth to ask on > the GDAL ML how to used this kind of data. GDAL and GRASS use proj4 for reprojection, but proj4 does not support these rotated spheres where the latitude origin for a longlat projection is not 0. The easiest solution is to use a different data source. Otherwise you would have to write a reprojection routine for such rotated spheres. The source code of gdalwarp or r.proj could be used as a template. Markus M > > some other things I've found in the web, e.g. > > https://gis.stackexchange.com/questions/10808/manually-transforming-rotated-lat-lon-to-regular-lat-lon > https://gis.stackexchange.com/questions/64210/transforming-regular-lat-lon-to-rotated-lat-lon > http://jgrib.sourceforge.net/docs/rotLatLon.pdf > [...] > > they looks similar you've found. > > > > > ----- > best regards > Helmut > -- > Sent from: http://osgeo-org.1560.x6.nabble.com/Grass-Users-f3884509.html > _______________________________________________ > grass-user mailing list > [email protected] > https://lists.osgeo.org/mailman/listinfo/grass-user _______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user