Grib1Product product = products.get( i );
crc32.reset();
crc32.update(product.getPDS().getPdsVars().getPDSBytes());
ByteBuffer bb = ByteBuffer.allocate(8);
bb.putLong( product.getPDS().getPdsVars().getReferenceTime() );
crc32.update(bb.array());
long crcv = crc32.getValue();
Integer recnum = pdsMap.get(crcv);
// duplicate found
if ( recnum != null) {
StringBuilder str = new StringBuilder( "Duplicate " );