Hi Janet: You cant use the long type in _writing_ to a netcdf file, since netcdf-3 doesnt support longs (8 byte ints). We could do an automatic conversion to, say, double. But if you are writing the IOSP, you should just decide what data type fits best. Sorry that the documentation is not clear.... Ticket Details =================== Ticket ID: UIT-326023 Department: Support netCDF Java Priority: Normal Status: Open