Hi Shawn, > I am an ITC student who used to work closely with OGC specifications. I > learned from your website that Unidata will provide the data use in the > Geosciences in the coming years. That is a thrilling news to me and I > have been searched around the website for relative documents. It may due > to my poor searching ability that I couldn't find descriptions about the > datum and coordinate system for the data model you're using now. There > is one illustration of the DOM, however, I can't get the idea of > vertical transformation and the other one. It would be nice if you can > give me a little bit heads-up about the datum and coordinate system > issue because they are crucial for GIS data. Thank you very much in > advance. Our data comes in a variety of forms and they don't really have a consistent method for containing datum and coordinate system information. We have software that recognizes the different conventions the data are stored in and determining coordinate system information. Much of the data we deal with is quite low resolution from a GIS perspective and many, even most, do not specify a datum. We are involved in a number of groups/projects that are working to standardize this kind of information: 1) CF (http://www.cgd.ucar.edu/cms/eaton/cf-metadata/CF-1.0.html) is a metadata convention for Climate and Forecast (CF) data that is stored in the netCDF file format. They are looking at various ways to encode this kind of information and are currently looking at WKT as an interim solution. 2) The GALEON project started as an OGC Interoperability Experiment. It has been working on mapping between netCDF data and OGC WCS. Our THREDDS WCS capabilities were developed out of this project. > Oh, if you don't mind. I am extremely curious about how you convert the > arbitrary grid shape into regular one when providing WCS in the latest > version. Would you please give me a hint about this too? Thanks a > million. I'm not sure what you mean by arbitrary grid shape. All the gridded data that we are serving through WCS have projection information that allows us to provide all the information needed by WCS. Hope this helps. Ethan Ticket Details =================== Ticket ID: GAL-491903 Department: Support THREDDS Priority: Critical Status: Open
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