Sets key/value pairs in the input GRIB file and writes each message to the output_grib_file. It fails when an error occurs (e.g. key not found).
grib_set [options] grib_file grib_file ... output_grib_file
Key/values to set. For each key a string (key:s), a double (key:d) or an integer (key:i) type can be defined. By default the native type is set.
Repack data. Sometimes after setting some keys involving properties of the packing algorithm a repacking of data is needed. This repacking is performed setting this -r option.
Set all the data values to "value".
Declaration of keys to print. For each key a string (key:s), a double (key:d) or an integer (key:i) type can be requested. Default type is string.
As -p adding the declared keys to the default list.
Where clause. Set is only executed for GRIB messages matching all the key/value constraints. If a GRIB message does not match the constraints it is copied unchanged to the output_grib_file. This behaviour can be changed setting the option -S. A valid constraint is of type key=value or key!=value. For each key a string (key:s), a double (key:d) or an integer (key:i) type can be defined. Default type is string. In the value you can also use the forward-slash character '/' to specify an OR condition (i.e. a logical disjunction) Note: only one -w clause is allowed.
Does not fail when the message has wrong length
Strict. Only messages matching all the constraints are copied to the output file
Multi-field support off. Turn off support for multiple fields in single GRIB message.
Copy GTS header.
GRIBEX compatibility mode.
Message type. T->GTS, B->BUFR, M->METAR (Experimental),A->Any (Experimental). The input file is interpreted according to the message type.
Force. Force the execution not to fail on error.
To set productDefinitionTemplateNumber=2 only for the fields with productDefinitionTemplateNumber=11
> grib_set -s productDefinitionTemplateNumber=2 -w productDefinitionTemplateNumber=11 ../data/tigge_pf_ecmwf.grib2 out.grib2
To set productDefinitionTemplateNumber=2 only for the fields for which productDefinitionTemplateNumber is not equal to 11
> grib_set -s productDefinitionTemplateNumber=2 -w productDefinitionTemplateNumber!=11 tigge_pf_ecmwf.grib2 out.grib2
When a key is not used all the bits of its value should be set to 1 to indicate that it is missing. Since the length (number of octet) is different from a key to another, the value that we have to code for missing keys is not unique. To give an easy way to set a key to missing a string "missing" or "MISSING" is accepted by grib_set as follows:
> grib_set -s scaleFactorOfFirstFixedSurface=missing,scaledValueOfFirstFixedSurface=MISSING ../data/regular_latlon_surface.grib2 out.grib2
To set scaleFactorOfSecondFixedSurface to missing only for the fields for which scaleFactorOfSecondFixedSurface is not missing:
> grib_set -s scaleFactorOfSecondFixedSurface=missing -w scaleFactorOfSecondFixedSurface!=missing tigge_pf_ecmwf.grib2 out.grib2
It is possible to produce a GRIB edition 2 file from a GRIB edition 1 by just changing the edition number with grib_set. However it is important that you carefully inspect the output and check the information is correctly translated.
grib_set -s edition=2 ../data/reduced_gaussian_pressure_level.grib1 out.grib2
With grib edition 2 is possible to compress data using the jpeg algorithm. To change packing algorithm from grid_simple (simple packing) to grid_jpeg (jpeg2000 packing):
> grib_set -s packingType=grid_jpeg ../data/regular_gaussian_model_level.grib2 out.grib2
It's possible to ask ecCodes to calculate the number of bits per value needed to pack a given field with a fixed number of decimal digits of precision. For example if we want to pack a temperature expressed in Kelvin with 1 digits of precision after the decimal point we can set changeDecimalPrecision=1
> grib_set -s changeDecimalPrecision=1 ../data/regular_latlon_surface.grib2 ../data/out.grib2