Hi Milan: Some comments are below. Milan Dragosavac wrote:
Hi John, The check some can be done only on particular format of the tables. Almost every bufr software ( centre) got different format of bufr tables although the content shall be the same in the case of standard WMO table entries. If local entries are added, the tables would be different anyway from centre to centre.
yes, you are right that it would require the use of a standard format. I think that this could be a good thing, even if centers decide to use a special format internally, it would be helpful to be able to translate that to a standard format for comparison.
Therefore checksum on tables would not work and really is not needed. Ecmwf is using bufr for more than 20 years and we have not had a case that we can not decode historical data because of tables.
i understand that ecmwf can decode the messages that ecmwf has written, since you have been careful to preserve all the tables that you need. But perhaps an outside decoder (such as the one i am trying to write) might have more trouble being sure that it has the correct tables?
If incompatible changes are introduced in new table versions in the future, and coders are not being careful about what version they put into the bufr record, then this may also cause problems. still, if they are careless about the version, they could be careless about the checksum also, so this solution is not foolproof either. thanks for your time in thinking about these issues. BTW, I have been cc'ing the email group so others can think about them also, and add their thoughts if they like. Ciao, John
Best regards Milan Milan Dragosavac