Hi Ling, At first glance this file does not seem to have lat/lon or a conventions attribute. I am moving this ticket to the Java-netcdf group here at Unidata and they will be able to shed some light on this. You can also look at some documentation on netcdf observation conventions: http://www.unidata.ucar.edu/software/netcdf-java/formats/UnidataObsConvention.html -Jeff Ticket Details =================== Ticket ID: TDW-710891 Department: Support IDV Priority: Normal Status: Open