frmts/nitf/nitfdataset.cpp calculates lat and long min and max incorrectly

[wlyons@…]

The lat offset and long offset are roughly the center point.  The SDE spec 
(STDI-0002) says the offset and scale normalize all the coordinates between -1 
and 1.  The current implementation uses the center point as the min values.

in nitfdataset.cpp line 881

solution:

sprintf( szValue, "%.16g", sRPCInfo.LONG_OFF - ( sRPCInfo.LONG_SCALE / 2.0 ) );
poDS->SetMetadataItem( "RPC_MIN_LONG", szValue );

sprintf( szValue, "%.16g", sRPCInfo.LONG_OFF + ( sRPCInfo.LONG_SCALE / 2.0 ) );
poDS->SetMetadataItem( "RPC_MAX_LONG", szValue );

sprintf( szValue, "%.16g", sRPCInfo.LAT_OFF - ( sRPCInfo.LAT_SCALE / 2.0 ) );
poDS->SetMetadataItem( "RPC_MIN_LAT", szValue );

sprintf( szValue, "%.16g", sRPCInfo.LAT_OFF + ( sRPCInfo.LAT_SCALE / 2.0 ) );
poDS->SetMetadataItem( "RPC_MAX_LAT", szValue );

[warmerdam]

Patch applied. 

thanks!