Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.

Re: [netcdf-java] Missing GRIB parameters in NetCDF?

  • To: Tor Christian Bekkvik <torc@xxxxxx>
  • Subject: Re: [netcdf-java] Missing GRIB parameters in NetCDF?
  • From: Robb Kambic <rkambic@xxxxxxxxxxxxxxxx>
  • Date: Mon, 24 Aug 2009 15:49:29 -0600 (MDT)
On Thu, 20 Aug 2009, Robb Kambic wrote:


On Thu, 20 Aug 2009, Tor Christian Bekkvik wrote:



Hi,
I am using NetCDF to read GRIB/GRIB2 files. Almost everything works fine, but some GRIB parameters seems to be unavailable via the NetCDF API. I this case, 
I could not find
       "RESOLUTION AND COMPONENT FLAGS (GDS OCTET 17)" from the GRIB file.
, at least not in the NetCDF attributes..

(Details: This GDS parameter from the GRIB file tells how to interpret
direction from combined U- and V- components. (In my case, current vectors from 
weather data)
Text from GRIB standards documentation:

      TABLE 7 - RESOLUTION AND COMPONENT FLAGS (GDS OCTET 17):
      Bit 5:
      0     u- and v-components of vector quantities resolved relative
              to easterly and northerly directions

      1     u and v components of vector quantities resolved relative
              to the defined grid in the direction of increasing x and y
              (or i and j) coordinates respectively

)

 

- How could we get this GRIB parameter ?






Tor,

The information is available in the CDM stack, ie

GridIndex index;

List<GridDefRecord> hcsList = index.getHorizCoordSys();
for (GridDefRecord gds : hcsList) {
  String windflag = gds.getParam(GridDefRecord.WIND_FLAG)
}
In my first response it was a mistake to move the discussion from the netCDF-Java library to the lower level GRIB library without an explanation. The purpose was to show you the code snipet of how the value was obtained. Hopefully I didn't confuse you. 


Robb...




 

Thanks,

Tor Chr Bekkvik

 

 

 





===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III Univ. Corp for Atmospheric Research 
rkambic@xxxxxxxxxxxxxxxx                   WWW: http://www.unidata.ucar.edu/
===============================================================================


===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III                      Univ. Corp for Atmospheric Research
rkambic@xxxxxxxxxxxxxxxx                   WWW: http://www.unidata.ucar.edu/
===============================================================================
  • 2009 messages navigation, sorted by:
    1. Thread
    2. Subject
    3. Author
    4. Date
    5. ↑ Table Of Contents
  • Search the netcdf-java archives: