First, what version TDS and ncWMS are you using?
Having said that, Im sure we can figure out the problem and a workaround.
Hi John, Sean Gaffney from BODC here. Roy Lowry suggested I get in touch with you in respect of an issue I’m having. We at BODC have been sent a set of CF compliant netcdf numerical model data which have time attributes of time:units = "days since -4713-01-01 00:00:00" ; time:calendar = " gregorian" ; This gives us time values which run from 2438396.5 to 2438761.5, which are equivalent to (in UT) 12:00 01/01/1964 to 12:00 31/12/2004. We told the originator to supply the time in these units so that the data would be interoperable with the SeaDataNet community we serve here in Europe, as they use this time standard. The problem occurs in that our numerical model delivery system runs in conjunction with some ncWMS visualisation software developed by Jon Blower at Reading. When the data are visualised, the time element becomes junk, giving values of 11000 for year. I’ve been in discussion with Jon and an associate of his from Reading, Guy Griffiths, and they informed us that the “Java-NetCDF libraries do not interpret ISO8601 dates before 0AD correctly, so if the calendar is set to "standard", "gregorian", or is missing, they will not be interpreted correctly”. Roy says that you are the person to talk to about these libraries so I was wondering could you provide any insight into what is happening with the interpretation of the time units as we supply them? There is an additional oddity in that, within THREDDS itself, which is what we use for interrogating the netcdf files, the times are recognised correctly and converted somehow to the right date and time in UT (see attached PNG). Neither ourselves nor Guy Griffiths at Reading understand where in the THREDDS software this translation occurs, so if you could throw some light on this for me as well, I’d greatly appreciate it. Thanks very much Sean Gaffney BODC
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