Thank You, It helps to know what to look for (GridIndex, GridDefRecord).
But It is still unclear how to get these, given a variable or its
Gridset:
mNCdataset = NetcdfDataset.openDataset(this.mFilename, true, null);
mNCgridDataset = new ucar.nc2.dt.grid.GridDataset(mNCdataset);
for (ucar.nc2.dt.GridDataset.Gridset gs :
mNCgridDataset.getGridsets())
{ for (GridDatatype gg : gs.getGrids())
{ VariableEnhanced variable = gg.getVariable(); //gets
U and V variables here.
...
(When interpreting and joining U&V variable components, info from
GridDefRecord etc. only gives meaning when associated with these
variables)
Regards,
Tor C
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/
