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Re: Supporting other data formats

On Apr 15, 2005, at 6:52 AM, Glenn Rutledge wrote:


This thread (pun intended) woke me up this Friday morning. WCS for OPeDNAP will be a great leap forward for our shop and BUFR- the WMO standard format for model input ("the BUFR tanks" at NCEP, Upper-Air collectives, and other data near and dear to NWP, goes a long way toward the implementation of a long awaited single (virtual) interface to for anyone doing Model Intercomparison Projects, or grib/NetCDF/BUFR... data analysis. We just wrote a BUFR decoder in perl to overcome some of our issues with BUFR (as listed below), so yes- NOMADS cares very much- more importantly users- last month we had 4M downloads, serving over 3.6Tb of data and several emails requesting BUFR access. NOAA has a requirement for BUFR decode/access and display as well.
So, the NCDC NOMADS shop will gladly test or otherwise try to help in this endeavor. Granted, we don't have the expertise to develop this- we do have some talent to install and flush out issues associated with these formats and interfaces thru OpeNDAP. One final note: Grib2 is on the horizon....COLA is very much aware of this but not a top priority. Anyone working this for GDS? Just wondering......

On the GIS/WCS front: Dan Holloway is taking a short vacation, but when he gets back he can provide first-hand information about the MapServer-OPeNDAP gateway. Briefly, MapServer uses the GDAL library to read from various sources. Frank Warmerdam and I have written a GDAL-DAP driver, so GDAL can be used to read from DAP servers. There are limits, but Frank took my driver code and spiffed it up quite a bit. He also wrote an OGR driver; OGR is the point data equivalent to GDAL (GDAL is designed to work with raster data). So OGR can be used to read from 'DAP Sequences' like the EPIC-DAP server from PMEL. Caveat: I haven't tested this myself.

On the BUFR front: There's been considerable interest in support for BUFR for a long time. I though that COLA was working on this? Can some one on DODS TEch comment?


Thanks to all for your leadership and vision in all this....Glenn

John Caron wrote:

Tennessee Leeuwenburg wrote:

Hi guys,

We're looking at phase two of the project I'm working on at the moment. Phase one involved hooking up our weirdo database to OpenDAP, and it looks that that will be a success. There's one thing that's not as wonderful as we might hope, and a couple of cool extra things we'd like to do.

In order to cope with observational data stored in BUFR format, we've had to write scripts for conversion to NetCDF prior to serving it with thredds. I don't really like messing about in thredds code if I can help it, on account of it makes code maintainance that much harder. So we convert to NetCDF on a product-by-product basis. But it would be way cool if we could serve BUFR data more generally and without the conversion step. So my question is : does anyone on this list care much about BUFR data, and is anyone thinking much about how it might fit into an OpenDAP context?

What kind of data is stored in BUFR?

We have an "I/O service provider" framework in netcdf-java version 2.2, where you can read non-native files as if they are netcdf files. We have done GRIB files in this way, among others. It would probably be very cool to be able to do that for BUFR files. If you're interested i can tell you more.

The other angle is from the GIS world rather than the data sharing world. We'd love to publish some of our data sets in such a way that GIS packages can read them. To the best of my knowledge, no GIS package reads OpenDAP or even NetCDF. This means we've either got to do a conversion step from NetCDF into something that the GIS packages can read, and then serve it out using a different server - like a shapefile server for instance. So we would have to choose specific products to make available, provide shapefile derivatives from our hi-res NetCDF data, and tell people to go look there. It's not the worst plan I've ever heard, but has anyone here heard about any efforts to integrate OpenDAP more tightly with GIS software?

The next version of the THREDDS server will have OpenDAP integrated into it. It will also have an experimental WCS server for gridded data. The idea is that anything that can be read in through netcdf-java version 2.2 can be served through opendap. If theres enough georeferencing, these can also be served through WCS. Again it would be cool to extend this to a WFS server for features, although it would be a lot of work.

We are also working with ESRI on their project to read in netcdf gridded files, and another project with GDAL/Cadcorp experimenting with netcdf over WCS. Still both in research stage.

-- Glenn K. Rutledge NOMADS Program Manager NOAA Meteorologist / Physical Scientist National Oceanic and Atmospheric Administration National Climatic Data Center 151 Patton Ave Asheville, North Carolina 28801 (828) 271-4097

The contents of this message are mine personally and do not necessarily reflect any position of the Government or the National Oceanic and Atmospheric Administration."

James Gallagher                jgallagher at opendap.org
OPeNDAP, Inc                   406.783.8663

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