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Example of reading string from NetCDF with netcdf-perl

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  • Subject: Example of reading string from NetCDF with netcdf-perl
  • Date: Tue, 4 Mar 1997 10:36:17 -0700 (MST)
#!/usr/local/bin/perl
#
#  Example on reading strings from a NetCDF file using netcdf-perl interface
#  Using a metar NetCDF file
#
#
use NetCDF ;

# process input parameters
if( $#ARGV == 0 ) {
        $ncfile = $ARGV[ 0 ] ;
} else {
        die "Wrong number of parameters " ;
}
# set error handling to verbose only
$result = NetCDF::opts( VERBOSE ) ;

# open or create ncfiles
if( -e $ncfile ) {
        $ncid = NetCDF::open( "$ncfile", RDWR ) ;

        # get value of dimension recNum in variable $recnum
        $recNum_id = NetCDF::dimid( $ncid, "recNum" ) ;
        $name_id =  "xxxxxxxx"  ;
        $recnum =  -1  ;
        NetCDF::diminq( $ncid, $recNum_id, $name_id, $recnum ) ;

        if( $recnum > 0 ) {

                # where to start getting info
                @start = ( 0, 0 ) ;

                # get value of dimension stn_name_len in $stn_name_len
                $stn_name_len_id = NetCDF::dimid( $ncid, "stn_name_len" ) ;
                NetCDF::diminq( $ncid, $stn_name_len_id, $name_id, 
                        $stn_name_len ) ;

                # How much to read
                @count = ( $recnum, $stn_name_len ) ;  

                # Initialize array to read into
                $StrLen = "\0" x $stn_name_len ;
                @STNS = ( $StrLen ) x ( $recnum ) ;

                # get id of variable stn_name in stn_name_id
                $stn_name_id = NetCDF::varid( $ncid, "stn_name" ) ;

                # read stations into @STNS array
                NetCDF::varget( $ncid, $stn_name_id, \@start, \@count, 
                                \@STNS ) ;

                # NetCDF treats strings as arrays, perl treats string as
                # scalars, so convert arrays to scalars for perl
                for( $i = 0; $i < $recnum; $i++ ) {
                        for( $j = 0; $j < $stn_name_len; $j++ ) {
                                $station .= chr( $STNS[ $j ] ) ;
                        }
                        print "Station = $station\n" ;
                        undef( $station ) ;
                }
        }
        $result = NetCDF::close( $ncid ) ;
} else {
        print "Can't find input file $ncfile\n" ;
        exit 0 ;
}
exit 0 ;


_______________________________________________________________________________
Robb Kambic                                Unidata Program Center
Software Engineer                          Univ. Corp for Atmospheric Research
address@hidden             WWW: http://www.unidata.ucar.edu/
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