Edition independent ecCodes/GRIB-API keys

ecCodes/GRIB-API provides high level access to the information in a GRIB message through a set of edition independent keys. The advantage in writing code using only those keys is that the resulting application is edition independent and can therefore process GRIB edition 1 or 2 transparently.

Namespaces

Some of the edition independent keys are grouped in namespaces for convenience.

The values of the keys in a namespace can be obtained from the GRIB just using the get instruction with the key name or with the key name prefixed by the namespace name. For example it is equivalent get shortName or parameter.shortName. The same is valid for the set instruction.

All the values of the keys belonging to a namespace can be printed with the -n option of grib_ls or with the keys iterator provided by the library.

The corresponding namespaces of two GRIB messages can be compared with grib_compare which is able to detect the keys of the enquired namespace having different values in the two messages.

The following is a list of the namespaces providing edition independent keys.

Data related keys

A set of edition independent keys is provided to have access to the data values and to select and control the packing method used.

KeyDescription
valuesData values.
packingTypeType of packing.
  • grid_simple
  • spectral_complex
  • spectral_simple
  • grid_simple_matrix
  • grid_complex
  • grid_complex_spatial_differencing
  • grid_jpeg
  • grid_jpeg
  • grid_png
  • grid_png
  • grid_ieee
  • grid_simple_log_preprocessing
  • grid_second_order

Disclaimer

The official copy of the FM-92 GRIB document from which the relevant information contained in the following pages is copied can be obtained from the WMO web site: http://www.wmo.int/pages/prog/www/WMOCodes.html