[gdal-dev] projection of (maybe broken) grib file

[Andre Joost]

Am 26.09.2014 13:51, schrieb teeschke:
> Hi list
>
> We have a grib file, that gets cropped after a projection from WGS84 to
> WebMercator. The issue occurs in UMN Mapserver and QGIS. ArcMap can project
> the grib file correctly - so I think its a GDAL thing.
>
> <http://osgeo-org.1560.x6.nabble.com/file/n5164353/grib_projection_cutting.jpg>
>
> Extracting the metadata with gdalinfo points out that the original corner
> coordinates are shifted a little bit.
>
> $ gdalinfo 2014-09-28T00\:00Z.grb
> Driver: GRIB/GRIdded Binary (.grb)
> Files: 2014-09-28T00:00Z.grb
> Size is 1440, 721
> Coordinate System is:
> GEOGCS["Coordinate System imported from GRIB file",
>      DATUM["unknown",
>          SPHEROID["Sphere",6367470,0]],
>      PRIMEM["Greenwich",0],
>      UNIT["degree",0.0174532925199433]]
> Origin = (-179.875000000000000,90.125000000000000)
> Pixel Size = (0.250000000000000,-0.250000000000000)
> Corner Coordinates:
> Upper Left  (-179.8750000,  90.1250000) (179d52'30.00"W, 90d 7'30.00"N)
> Lower Left  (-179.8750000, -90.1250000) (179d52'30.00"W, 90d 7'30.00"S)
> Upper Right ( 180.1250000,  90.1250000) (180d 7'30.00"E, 90d 7'30.00"N)
> Lower Right ( 180.1250000, -90.1250000) (180d 7'30.00"E, 90d 7'30.00"S)
> Center      (   0.1250000,   0.0000000) (  0d 7'30.00"E,  0d 0' 0.01"N)

90° N can not be projected to Web Mercator (it would be in infinity), so 
+/-90.125 can also not be reprojected correctly.

Cut your file to +/-179.9/89.9 degrees, then try again the reprojection 
with gdalwarp.

HTH,
André Joost