Description and Format of CREX Tables B and D
To view the sample CREX tables, click on Sample CREX Table B file and Sample CREX Table D file.
Every CREX message that is presented to the CREXLIB software, either for input (reading/decoding) or output (writing/encoding) purposes, must have CREX tables associated with it, which exist as separate ASCII files. It is extremely important that each of these tables not only be syntactically correct but also complete, in the sense that it contains all the necessary descriptors needed for encoding or decoding the CREX message. The WMO version of these tables contain all the approved CREX descriptors. The user has the choice of using the WMO version of these tables which contain all the current CREX descriptors and can be downloaded from "Official Internationally-Coordinated WMO BUFR-CREX Tables", or using a subset of these tables that consist only of the descriptors that are needed.
The first entry in each record of Table D is a sequence descriptor. It is followed by the list of descriptors it defines. This list may consist of element descriptors, replication descriptors, operator descriptors and sequence descriptors. The last descriptor in each list is followed by the # character which serves as a marker to the CREXLIB software of the location of the end of the list.