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> Organization: NCAR / MMM > Keywords: 199502282325.AA15817 Hi David, > One of the ideas I had at the back of my head when I was talking to you > and Joe last fall was to try to find out whether there was (still) enough > commonality between netCDF and TDF that at least some subsets of either > data system might be functionality equivalent. For example, Joe already > has what he calls an "instant" routine (for "instantiate") which resolves > many of the advanced TDF features such as variable links and external > references that may not have an equivalent in netCDF. Even if a full > implimentation of TDF supports things that are foreign to netCDF it > seemed to me that the most basic version of a data file wouldn't necessarily > have to make use of all the features of the complete data model. Thus > through a routine very similar to "instant", you might be able to produce > a fully acceptable TDF file that is still compliant with netCDF (with the > possible exception of a data header or the like). Similarly, having some > form of a fully acceptable netCDF data set, perhaps with some restrictions > on data packing or the like, that would also be acceptable to Sea Space's > Terascan software (and TDF implimentation) is real attractive. That would > facilitate data exchange, without requiring either data system to fully > support all the features of the other system and with the need for a formal > file conversion filter. In that case, cross data set compatibility could > be consider a user "option" that could be invoked, if desired. I think the fact that netCDF encodes all the data using XDR whereas TDF doesn't use XDR makes it impractical to make use of data among TDF- and netCDF-based applications without an actual file conversion program. Every netCDF dataset has all its values as well as the header information encoded using XDR. --Russ