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Hi Jon and others, In response to the suggestion that users in the traditional GIS community can't make use of CF-netCDF files, there exists a fairly simple WCS use case that has worked for a couple years now in getting data in a useful CF-netCDF form to traditional GIS users -- most notably users of arcGIS in the hydrology and human impacts disciplines. In this case, the WCS client module is a very simple one that knows virtually nothing about CF-netCDF but does know how to use getCapabilities to learn what coverages are available, describeCoverage to request information about those coverages, and then getCoverage with a 3D bounding box, coverage name, and time specified in order to get back a CF-netCDF file that's stored on local disc. Since the release of arcGIS 9.2, the processing and display modules in arcGIS are able to read such CF-netCDF files and work with them. I've been working with several arcGIS users in academia and governement who have incorporated such a simple (python based) WCS client into arcGIS processing chains that make use of the sophisticated database operations and map display capabilities that GIS users are accustomed to. Please note that this is NOT an argument against geoTIFF output. Also there are many important use cases where it's important to have the WCS client read the coverage data directly into memory rather than into a file on local disk. And I am not arguing against an option that allows a client to request a OPeNDAP URL be returned by a getCoverage request. For certain applications, those are important options. But my point is that it has already been demonstrated that a large amount of useful work can be done with CF-netCDF datasets using traditional GIS systems by employing simple WCS client module that need not understand CF-netCDF itself but can gather information and request subset coverages in the form of a CF-netCDF file. The practicality and usefulness of the latter approach has already been proven by real users. Moreover Dominic Lowe's addition of a WCS client library to the open source OWSLib has made it even more straightforward to implement. So let's make sure we keep this option in the mix. -- Ben On Mon, Sep 29, 2008 at 9:05 AM, Jon Blower <jdb@xxxxxxxxxxxxxxxxxxxx>wrote:
Hi Peter, > wouldn't it be nice to store NetCDF and get out GeoTIFF slices at some time? Yes! IMHO think this will do more for "GIS interoperability" than working out how to have NetCDF as an *output* format. (Again, I repeat my worry about the "core plus extension" model...) Regarding your other points, yes, with enough effort we could figure out how to force CF-NetCDF through WCS without loss of information (although WCS will be years behind the curve of scientific innovation for the foreseeable future unless we get Roy's suggested $700bn bailout). My argument remains that this isn't what we really need. We need to present metocean data in a form that others can understand. Having another way to download CF-NetCDF doesn't help those who can't understand CF-NetCDF. Cheers, Jon
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