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Re: [netcdf-java] Decoding NDFD Severe Weather product Problem

Jeff.
GetLocalUseSection attached, made changes so all local use sections are being written out. These ascii identifiers are similar to the METAR bulletins identifiers for weather. 

Robb...


On Wed, 5 Jan 2011, Jeff Brogden wrote:


Robb,


Hi Jeff,
The current grib decoder doesn't have a path to access the LocalUseSection directly. The grib library needs to be refactored to permit this option. With that being said, attached is a standalone program called GetLocalUseSection that takes 1 or 2 parameters, input Grib file and optional output file that reads the LocalUseSection of the first record in the Grib file. Since my test cases didn't have any files that use the LocalUseSection the code is untested. Could you send a sample file so it can be added to the test cases? My thinking was you could decoder the LocalUseSection and then add those parameters. Hopefully this will provide a path to the LOcalUseSection until the Grib Library can be refactored.
I did not receive an attachment with your email. I don't know if the list stripped it or not. If you could send it to me again, I would appreciate it. Thanks,
Here's an url from NDFD about LocalUseSection( section 2 ). From the documentation, it imples that these parameter might be static, could just 
be my interpretation.
From my understanding, and from looking at several data files, the table matches an integer to a string. In one case, 1 might be AS.Y and the next time, 1 might be SC.Y. What each integer maps to changes based on the warnings issued at that time. The text AS.Y and SC.Y, however, mean the same thing each time. So, there is no way of knowing what the integers stored in the data section refer to without the table in the LUS to decode them. 

Thanks for helping with this problem!

--
=======================================================================
Jeff Brogden    CIMMS/OU
address@hidden



===============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer II                       Univ. Corp for Atmospheric Research
address@hidden             WWW: http://www.unidata.ucar.edu/
===============================================================================
/*
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 * University Corporation for Atmospheric Research.
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 * any fee or cost, to use, copy, modify, alter, enhance and distribute
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 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
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/**
 * User: rkambic
 * Date: Jan 4, 2011
 * Time: 12:50:08 PM
 */

package ucar.grib.grib2;

import ucar.unidata.io.RandomAccessFile;

import java.io.*;
import java.util.ArrayList;
import java.util.List;

public class GetLocalUseSection {

  public static void main( String args[] ) {
    RandomAccessFile raf = null;
    Grib2Record firstRecord = null;
    try {
      PrintStream ps = System.out;
      if (args.length == 2 ) {  // input file, output file
        raf = new RandomAccessFile(args[0], "r");
        ps = new PrintStream(
                new FilterOutputStream(
                        new FileOutputStream(args[1], false)));
      } else if (args.length == 1) {
        raf = new RandomAccessFile(args[0], "r");
      } else {
        System.exit(0);
      }
      raf.order(RandomAccessFile.BIG_ENDIAN);
      Grib2Input g2i = new Grib2Input(raf);

      // params getProducts (implies  unique GDSs too), oneRecord
      raf.seek(0);
      g2i.scan(false, false);

      List<Grib2Record> record = g2i.getRecords();
      for( Grib2Record g2r : record ) {
        byte[] lus = g2r.getLocalUseSection() ;
        if( lus != null || lus.length != 0 ) {
          // packing method
          System.out.println( lus[0]);
          // account for the packing method, so start with 1
          //ps.write( lus, 1,  lus.length -1 );
          for( int i = 1; i < lus.length; i++ )
            ps.print( lus[ i ] +" ");
          ps.println();
        }  
      }

      ps.flush();
      ps.close();

      raf.close();    // done reading

      // Catch thrown errors from GribFile
    } catch (FileNotFoundException noFileError) {
      System.err.println("FileNotFoundException : " + noFileError);
    } catch (IOException ioError) {
      System.err.println("IOException : " + ioError);
    }
  }


}