eccodes/tools/grib_set.sh

#!/bin/sh
set -e

echo "-# To set productDefinitionTemplateNumber=2 only for the fields with productDefinitionTemplateNumber=11 \\n
\\verbatim
>grib_set -s productDefinitionTemplateNumber=2 -w productDefinitionTemplateNumber=11 ../data/tigge_pf_ecmwf.grib2 out.grib2
\\endverbatim\\n"

echo "-# To set productDefinitionTemplateNumber=2 only for the fields for which productDefinitionTemplateNumber is not equal to 11 \\n
\\verbatim
>grib_set -s productDefinitionTemplateNumber=2 -w productDefinitionTemplateNumber!=11 tigge_pf_ecmwf.grib2 out.grib2
\\endverbatim\\n"

echo "-# 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:\n
\\verbatim
>grib_set -s scaleFactorOfFirstFixedSurface=missing,scaledValueOfFirstFixedSurface=MISSING ../data/regular_latlon_surface.grib2 out.grib2
\\endverbatim\\n
Since some values cannot be set to missing you can get an error for those keys.\\n"

echo "-# To set scaleFactorOfSecondFixedSurface to missing only for the fields for which scaleFactorOfSecondFixedSurface is not missing: \\n
\\verbatim 
>grib_set -s scaleFactorOfSecondFixedSurface=missing -w scaleFactorOfSecondFixedSurface!=missing tigge_pf_ecmwf.grib2 out.grib2
\\endverbatim\\n"

echo "-# 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.
\\verbatim 
grib_set -s edition=2 ../data/reduced_gaussian_pressure_level.grib1 out.grib2
\\endverbatim\\n
For more details please see: https://confluence.ecmwf.int/display/UDOC/Converting+edition+1+to+2+-+ecCodes+GRIB+FAQ\\n"

echo "-# 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):\\n
\\verbatim 
>grib_set -s packingType=grid_jpeg ../data/regular_gaussian_model_level.grib2 out.grib2
\\endverbatim\\n"

echo "-# 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 \\n
\\verbatim 
>grib_set -s changeDecimalPrecision=1 ../data/regular_latlon_surface.grib2 ../data/out.grib2
\\endverbatim\\n"