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On Tue, 27 May 2003, Jim Cowie wrote: > > Hi Robb, > > Here's my $0.02: > > 1) GRIB2 support - you didn't mention this but I really hope that support > for GRIB2 is included. Last I heard, the NWS is going to start using > this before too long. Hiya Jim, Yes there will definitely be grib2 support. I'm actually working on this now. > > 2) The biggest problem we have with gribtonc is that all the product > tables are hard-coded. We often get grids from FSL or elsewhere > which don't use the NCEP grib tables, so we have to modify the code. > Externalizing this to a set of (optional) tables would solve this > problem. > Yea, hard coding tables is bad. Actually I've been working on making XML files of all the tables. So far, I've got more than 25 tables. The tables are located at: http://www.unidata.ucar.edu/projects/THREDDS/tech/index.html#STD I would like to hear comments about the tables. Robb... > -jim > > > > Robb Kambic wrote: > > Hiya, > > > > I'm writing to inform you about some proposed changes to the output > > netCDF files produced by the gribtonc (GRIB-to-netCDF) decoder. There > > are about 35 sites that have installed the decoders package as far as I > > know. I'm currently in the process of updating the package, including > > the CDLs to make them more useful and to add attributes required by > > new conventions. > > > > The original CDLs followed the NUWG conventions: > > > > http://www.unidata.ucar.edu/packages/netcdf/NUWG/ > > > > which haven't been modified in several years, > > > > Lately the CF conventions > > > > http://www.cgd.ucar.edu/cms/eaton/cf-metadata/index.html > > > > are becoming established as a more complete set of conventions for > > model output. Also, we are considering including spatial and temporal type > > variables to make the NetCDF file more GIS compatible. Another idea is to > > enhance the metadata about the date for THREDDS servers and other NetCDF > > clients. > > > > The CDL variable names will continue to follow the NUWG conventions > > for backward capability. The long_name attribute has been standardized > > by concatenation of the NUWG variable name plus the NUWG level name > > using the word "at" as a connector. So, the T_trop long_name is > > "Temperature at tropopause" in all the CDLs. This supports > > consistency in applications such as Unidata's IDV (Integrated Data > > Viewer). For similar reasons, we are adding attributes required by > > other conventions such as CF, such as the standard_name attribute. A > > sample variable will look like: > > > > float T_trop(record,y,x) ; > > T_trop:long_name = "Temperature at tropopause" ; > > T_trop:standard_name = "air_temperature" ; > > T_trop:units = "degK" ; > > T_trop:GRIB_parameter_number = 11 ; > > T_trop:GRIB_level_flag = 7 ; > > T_trop:_FillValue = -9999.f ; > > T_trop:navigation = "nav" ; > > > > > > Some other additions to the variable attributes are the > > GRIB_parameter_number, > > and the GRIB_level_flag attributes. These are being included so other > > conventions may refer to the NCEP GRIB tables as a cross reference. This > > will > > permit more flexible usage for the NetCDF files. > > > > Another variable has been added called forecast_time, a human readable > > string representing the valid forecast times. To make the data > > monotonically increasing, the code sets records for all the valid times in > > the > > netCDF file on initialization. > > > > When netCDF GIS applications become available, the new NetCDF files > > will already have the needed information for correct display. We are also > > considering temporal variables so time bounding boxes can be created for the > > datasets. > > > > This is a brief summary of the kind of modifications we are making to > > the decoders package. If you have other ideas about what should be > > included or omitted, please send in your comments. > > > > > > Robb... > > =============================================================================== > > Robb Kambic Unidata Program Center > > Software Engineer III Univ. Corp for Atmospheric > > Research > > address@hidden WWW: http://www.unidata.ucar.edu/ > > =============================================================================== > > > -- > Jim Cowie > NCAR/RAP > address@hidden > 303-497-2831 > > =============================================================================== Robb Kambic Unidata Program Center Software Engineer III Univ. Corp for Atmospheric Research address@hidden WWW: http://www.unidata.ucar.edu/ ===============================================================================