1. Run grib_filter with the rules files ‘print.filter’, ‘write.filter’, ‘transient.filter’ on ‘tigge.grib’
- Comment/uncomment the instructions one by one to see the different behaviours
Advanced grib_filter challenges
1. Change the date to 20160301 and the step to step+48 in the file ‘tigge.grib’ only for the data produced by ECMWF.
2. Set the values of the first message in the file ‘tigge.grib’ to 1.2, 3.4, 5.6, 3.7 and step to 72. Write only this message to the file ‘question2.grib’
- Check the values coded with grib_get_data or grib_dump.
3. Append to ‘question2.grib’ all the messages containing the same parameter of the other centres that are not encoded using a reduced Gaussian grid, setting the step to 72.
4. Split ‘tigge.grib’ into several files, one for each centre, containing only surface parameters and parameters that are at level 10 of height above ground.
- For the surface parameters, set changeDecimalPrecision to 2,
- For the height above ground parameters set changeDecimalPrecision to 3.
Print information messages for each case, such as:
Centre ammc parameter v not written Centre ammc parameter 10u written to question4-ammc.out
5. Merge the messages from the previously split GRIB files into a single file
- Write only messages encoded in a regular lat-long grid, and exclude messages where the parameters are 10u or 10v.The