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Re: [netcdf-java] Announcing Netcdf-Java / CDM version 4.3.8 BETA and emergency shutdown procedures

Hi Don:

On 2/9/2012 1:45 PM, Don Murray wrote:

Glad you are making progress on this.  I am looking forward to the new calendaring stuff for the climate work we do at NOAA.  Currently the IDV does not correctly handle the non standard calendars.

A couple of questions/issues:

- you say that the variable names have changed between 4.2 and 4.3 for GRIB files.  What is the extent of these changes and when do you expect these will be used in the TDS?  The IDV relies on the variable names to look up parameters in bundles, to associate user preferences for displays (color table, units, contouring information) and the variable name is encoded in bundles to they always get the same data.  So, if the variable names are different than before, that will mean that IDV bundles accessing TDS servers using the 4.3 library will be broken. That would be a major problem for the IDV community.

the names have to change for lots of reasons. some background is here:


the previous algorithm tried to modify the names based on what other variables with the same parameter exists in the same file. but this breaks aggregation and has other, subtle effects that are not maintainable. plus there are lots of errors in 4.2 tables. plus intervals were ignored, and statistical types not always handled well, etc.  The previous GRIB handling is flawed enough that I think that users need to repick which variables they really want. I think the IDV is going to have to develop a graceful way to allow bundles to evolve.

however, im not particular happy with the what i have. for one thing, tables get tweaked, eg by the WMO. Also, we may realize that some obscure field in the PDS must be added to the name. ugh.

its possible that an opaque id is a better idea, with all semantics in the long name. Another alternative is what NCL does with their encoding, see:


im open to other suggestions.

- On the netCDF-Java documentation page, there is a link to the 4.3 ncIdv.jar.  This does not work with the IDV, so I would suggest removing that until it does to avoid unnecessary support requests.

ok, thanks. we plan to integrate 4.3 and IDV when Yuan gets back from his trip.


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