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Hi Tommy, Sorry I've taken so long to deal with your question. It sort of fell through the cracks, and I just noticed today that it hadn't been answered yet. For representing georeferenced gridded data in netCDF, we have some examples that we worked out a couple of years ago. These use a dummy dimension "nav" and the convention that every variable that uses the "nav" dimension is specifically for georeferencing. If there is only one georeferencing in a netCDF file, the nav dimension is of size 1, but it could be larger for multiple sets of variables, where each set uses a different value of nav to describe its georeferencing. Some examples of this convention are in the directory ftp://ftp.unidata.ucar.edu/pub/netcdf/cdl/ for example ruc.cdl representing the RUC/MAPS model on a Lambert Conformal grid. I wrote a paper about another approach to georeferencing: Rew, R. K., 1998: <a href="http://www.unidata.ucar.edu/staff/russ/MapGeoGrid/ams98.html"> Georeferencing with Java: An Example of Executable Metadata.</a> <em>Proceedings, 14th International Conference on Interactive Information and Processing Systems for Meteorology, Oceanography, and Hydrology,</em> American Meteorological Society, January, Phoenix, Arizona. The slides used in the presentation, and the source code for the prototype, are also <a href="http://www.unidata.ucar.edu/staff/russ/MapGeoGrid/index.html">available online.</a><p> Of course there are other georeferncing conventions worked out by other groups, e.g. the COARDS conventions. For more of these, see the netCDF Conventions page at http://www.unidata.ucar.edu/packages/netcdf/conventions.html --Russ >>>>> "Tommy" == Tommy Jasmin <address@hidden> >>>>> wrote the following on Mon, 02 Nov 1998 15:33:09 +22304808 > guys - > as you may know, I recently wrote a couple of NetCDF related applications > here at SSEC. one, a Java-based McIDAS area to NetCDF converter that > works (well) only on GVAR data. the other, a more general ADDE server > in C that works on any data type, and utilizes the McIDAS library to do > calibration on the fly. > one big concern and ongoing source of debate is that there is no standard > for representing geographic image data in NetCDF format that I know of. > Tom Whittaker would like me to take a 1st shot at proposing something. > I was just wondering if you could give me any general advice, references > for information, etc. > a specific question I have is whether there are examples of CDL where > certain variables or attributes are present conditionally based on > the data source. the reason I ask this is because I don't want to > assume the data source is a McIDAS area file, and if there are different > possible input formats, then there may be some variables or attributes > that are only relevant to a certain format. > ------------------------------------------------------------------------- > * | * / + > + --*-- / Tommy Jasmin > | + | + / + * Interactive Systems Development Group > --*-- / University of Wisconsin > | * / | Space Science and Engineering Center > + / --*-- address@hidden > * / | http://www.ssec.wisc.edu/~tommyj > * > -------------------------------------------------------------------------