cdm/src/main/java/ucar/nc2/iosp/nids/Nidsheader.java
public boolean isValidFile( ucar.unidata.io.RandomAccessFile raf) {
        try
        {
            long t = raf.length();
            if(t == 0){
                throw new IOException("zero length file ");
            }
        }
        catch ( IOException e )
        {
            return( false );
        }

        try{
            int p = this.readWMO( raf );
            if( p == 0 ) return false; // not unidata radar mosiac gini file
        }
        catch ( IOException e )
        {
            return( false );
        }
        return true;
    }
public boolean isValidFile( ucar.unidata.io.RandomAccessFile raf) {
        try
        {
            long t = raf.length();
            if(t == 0){
                throw new IOException("zero length file ");
            }
        }
        catch ( IOException e )
        {
            return( false );
        }

        try{
            int p = this.readWMO( raf );
            if( p == 0 ) return false; // not unidata radar mosiac gini file
        }
        catch ( IOException e )
        {
            return( false );
        }
        return true;
    }
public boolean isValidFile ( ucar . unidata . io . RandomAccessFile raf ) { try { long t = raf . length ( ) ; if ( t == 0 ) { throw new IOException ( "zero length file " ) ; } } catch ( IOException e ) { return ( false ) ; } try { int p = this . readWMO ( raf ) ; if ( p == 0 ) return false ; // not unidata radar mosiac gini file
 } catch ( IOException e ) { return ( false ) ; } return true ; }
check if this file is a nids / tdwr file
@param raf    input file
@return  true  if valid
check if this file is a nids / tdwr file