GRIB messages whose packingType is "grid_complex_spatial_differencing" are not fully supported in Metview computations. Therefore it is recommended to convert this data into "grid_simple" packing. This can done in Metview from version 5.17.0 using grib_set:

Python code:

f = mv.grib_set(f, ["packingType", "grid_simple"], repack=True)

Macro code:

f = grib_set(f, ["packingType", "grid_simple"], "repack")

In older Metview versions the repack option is not available, so the same conversion has to be done outside Metview using ecCodes command line tools (see here).

2 Comments

  1. Shahram Najm

    There is also this extra key to be set
    bitmapPresent=1

    So the full command in ecCodes would be:
    grib_set -r -s bitmapPresent=1,packingType=grid_simple in.grib out.grib

  2. Sandor Kertesz

    Why do we need that? I mean it is only needed for certain types of "grid_complex_spatial_differencing" fields, not for all.