Re: [netcdf-java] Parsing GRIB2 files from NOAA

yep, you get to read the data through the netCDF API.

On 1/16/2014 1:53 PM, Alejandro Villamarin wrote:
Hi again,

Ok...so if I understood correctly...I should be able to get the data
somehow right? Just asking because I'll need to know if I should stop
right now or keep using NetCDF-Java (which I think is great, by the way)

Regards,
Alejandro


On Thu, Jan 16, 2014 at 9:50 PM, John Caron <caron@xxxxxxxxxxxxxxxx
<mailto:caron@xxxxxxxxxxxxxxxx>> wrote:

    Hi Alejandro :

    well, thats complicated. the short answer is that we map collections
    of GRIB records to netcdf multidimensional arrays.

    you could read this as background:

    
http://www.unidata.ucar.edu/blogs/developer/en/entry/dataset_schemas_are_lost_in

    you can use lower level GRIB APIs, but we dont support or document
    them, and you would have to read code to understand how to use them.

    download ToolsUI and use it to read your GRIB file so you get a
    sense of it:

    
http://www.unidata.ucar.edu/software/thredds/v4.4/netcdf-java/documentation.htm

    Open in the Viewer tab; also open in
    IOSP/GRIB1(2)//GRIB1(2)Collection which shows you the underlying
    GRIB recordss.


    John

    On 1/16/2014 1:31 PM, Alejandro Villamarin wrote:
     > Hello John,
     >
     > Thanks for your quick response. I'm a newbie with both GRIB and
    NetCDF,
     > but I don't see a relationship between the NetcdfFile methods and the
     > GRIB structure (so far, I'm reading this:
     > http://www.wmo.int/pages/prog/www/DPS/FM92-GRIB2-11-2003.pdf).
    For instance:
     >
     > String filename = "gfs_4_20140115_1200_192.grb2";
     >          NetcdfFile ncfile = null;
     >          try {
     >              ncfile = NetcdfFile.open(filename);
     >
     >              List<Dimension> dimensions = new ArrayList<Dimension>();
     >              dimensions =  ncfile.getDimensions();
     >              Iterator<Dimension> iterator = dimensions.iterator();
     >              while (iterator.hasNext()){
     >                  Dimension current = iterator.next();
     >                  current.toString();
     >              }
     >
     > How are the dimensions mapped into the structure of a GRIB file? Same
     > goes for the getVariables() method...thus, that's why I was
    asking for a
     > full working example of parsing a GRIB file :)
     >
     > Regards,
     > Alejandro
     >
     >
     > On Thu, Jan 16, 2014 at 2:56 PM, John Caron
    <caron@xxxxxxxxxxxxxxxx <mailto:caron@xxxxxxxxxxxxxxxx>
     > <mailto:caron@xxxxxxxxxxxxxxxx <mailto:caron@xxxxxxxxxxxxxxxx>>>
    wrote:
     >
     >     Hi Alejandro:
     >
     >     You just open a GRIB file like its a netcdf file and access it
     >     through the netCDF API.
     >
     >     some tutorials are at:
     >
     >
    
http://www.unidata.ucar.edu/software/thredds/v4.4/netcdf-java/tutorial/index.html
     >
     >     John
     >
     >
     >     On 1/16/2014 5:08 AM, Alejandro Villamarin wrote:
     >>     Hi there!
     >>
     >>     I'm wondering if I can use NetCDF-Java library to parse GRIB2
     >>     files. So far I'm able to open and display file contents from a
     >>     GRIB2 file, but I'm wondering if it is possible to actually
    parse
     >>     the file: go through the variables and get the values,
    basically.
     >>     If so...are there any examples?
     >>
     >>     Kind regards,
     >>     Alejandro
     >>
     >>
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