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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
The gbx index is specific to each file, so cant be shared between files. A description is at http://www.unidata.ucar.edu/software/decoders/grib/javadoc/IndexFormat.txt this page has some info on how to create indexes: http://www.unidata.ucar.edu/software/decoders/ let me know if thats not clear enough. TDS = "THREDDS Data Server" Bill Moninger wrote: > Hi John, > > thanks for your quick response. > > If I'm going to use a single index (to save time), it can't be named > <filename>.gbx, because I want to use one index file for multiple grib > files, so I can save the time of making an index each time I read a > similar file. I'm assuming the index is a property of the particular > fields that are in a file, but not values in the field. If the indices > differ depending on the data in the files, then this obviously won't work. > > If it can work, then I'd like to specify a specific index file, like > 'RR.gbx' to work for all the RR (Rapid Refresh model, actually) files. > > By the way, what is "TDS"? > > -Bill > > On 2/9/2009 4:14 PM, John Caron wrote: >> Hi Bill: >> >> If you create the indexes externally, the library will use them (they better >> be right!). They must >> be named <filename>.gbx, and placed in the DiskCache.setRootDirectory(). >> >> For Grib files, I just noticed that theres some more stuff you have to do. >> In 4.0, the policy is set >> seperately from DiskCache. So you need to call >> >> GribServiceProvider.setIndexAlwaysInCache( true); // force use the cache >> for grib index >> >> You probably also want to set >> >> GribServiceProvider.setIndexExtendMode( IndexExtendMode.none); // never >> write an index >> GribServiceProvider.setIndexSyncMode( IndexExtendMode.none); // never sync >> the index >> >> this means that the index will never be created by the library, which is >> needed if you are in a >> multi-threaded situation like on a server. This is what the TDS does. >> >> Ill add this to the docs. >> >> Id like to hear what is your use case that might require this? >> >> >> Bill Moninger wrote: >>> Hello, >>> >>> I understand that I can use >>> DiskCache.setRootDirectory("grib_data"); >>> to set a directory where grib index files will be stored. This allows me >>> to read and process grib files from a read-only directory. >>> >>> However, I recall reading that it is possible to use a pre-defined index >>> file to save the time involved in generating an index file. In spite of >>> a lot of looking I haven't (re)found the documentation that tells me how >>> to do it. >>> >>> My question: how do I tell the netcdf4 reader to use a specified index >>> file (and one that is in a different directory than the data files)? >>> >>> -Bill >
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