Re: 20050927: Some general question about thredds/opendap

Ethan,

I have a question - Will the aggregation server expand at some point  
to include ADDE or OpenADDE?

Thank you so much!

Matthew

On Sep 27, 2005, at 1:22 PM, Ethan Davis wrote:

> Hi Heiko,
>
> Heiko Klein wrote:
>
>
> > I'm evaluating the usage of thredds for an EU project http:// 
> > www.ecmwf.int/research/EU_projects/GEMS/
> >
> > I installed the 2.0 version and was able to browse some pages and  
> > see some data, but I still have some more general questions:
> >
> > What are the main advantages of thredds against opendap?
>
> THREDDS is not a replacement for OPeNDAP. THREDDS adds cataloging  
> capabilities on top of various data access systems. The aggregation  
> server (and the upcoming 3.1 THREDDS server) provide both OPeNDAP  
> and THREDDS services.
>
>
> > I see a lot of XML files and the last s in thredds is for  
> > services: What is the relation between thredds and web-services  
> > (http://www.w3.org/2002/ws/) or REST (http://www.xfront.com/REST- 
> > Web-Services.html).
>
> Well, THREDDS catalogs are XML documents available over HTTP.  
> Catalogs can reference other catalogs and can also provide links  
> for accessing datasets. Besides catalogs, there are a number of  
> other THREDDS services available. For instance, the Dataset Query  
> Capabilities (DQC) allows users to request a subset of a dataset  
> collection. Current THREDDS services don't use any of the WS  
> frameworks, so I'd say THREDDS is built on "web services" but not  
> "Web Services".
>
>
> > Does thredds include a opendap server (didn't manage to get that  
> > working), or is thredds just able to distribute data via an  
> > external opendap server. If yes: Is the thredds opendap server  
> > able to serve as much data as the generic opendap servers, i.e.  
> > grib,hdf4,hdf5?
>
> The current 2.0 THREDDS server includes the aggregation server  
> which can serve netCDF files (and OPeNDAP dataset) individually or  
> aggregated. The upcoming 3.1 THREDDS Data Server can serve all the  
> data that the netCDF-java library can read (nc, GRIB-1 and -2, most  
> HDF5, NEXRAD level II and III, and a few others; see the netCDF- 
> java page for more details ,http://www.unidata.ucar.edu/software/ 
> netcdf-java/).
>
>
> > What is the status of thredds (3.0?), the aggregation server and  
> > the query language to search the aggr. server?
>
> The THREDDS Data Server (TDS) 3.1 will be released shortly. The  
> aggregation server is being refactored and will be folded into the  
> TDS at some future date. I'm not sure what you mean by "query  
> langague to search the agg server". The DQC (which I mentioned  
> above) is the only query language we are working on and it is not  
> widely used at this point. But it isn't specific to the agg server.
>
> Hope this clears things up. Let me know if you have other questions.
>
> Ethan
>
>
> > Best regards,
> >
> > Heiko
> >
> > --
> > Dr. Heiko Klein                              Tel. + 47 22 96 33 44
> > Air pollution Section/Research Department    Fax. + 47 22 69 63 55
> > Norwegian Meteorological Institute           http://www.met.no
> > P.O. Box 43 Blindern  0313 Oslo NORWAY       http://www.emep.int
>
> --
> Ethan R. Davis                                Telephone: (303)  
> 497-8155
> Software Engineer                             Fax:       (303)  
> 497-8690
> UCAR Unidata Program Center                   E-mail:     
> address@hidden
> P.O. Box 3000
> Boulder, CO  80307-3000                       http:// 
> www.unidata.ucar.edu/
> ---------------------------------------------------------------------- 
> -----

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Matthew Lazzara -Meteorologist- Antarctic Meteorological Research Center
947 Atmospheric, Oceanic and Space Sciences    http://amrc.ssec.wisc.edu
Space Science and Engineering Center       E-mail: address@hidden
University of Wisconsin-Madison                    Phone: (608) 262-0436
1225 West Dayton Street, Madison, WI 53706           Fax: (608) 263-6738
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