Re: Question about TDS OpenDAP

Thanks john. So basically I should tell the user that he should grab the 
file locally to be used for ncdump, unless it can work with OpenDAP 
directly).

This clarifies a lot. I did see an OpenDAP server somewhere with a 
download as NetCDF button, which apparently did the trimming and packed 
the result into a NetCDF file. Is there any though about doing something 
like this in TDS?

Thanks,
Estani
Am 17.01.2012 17:38, schrieb John Caron:
> Hi Estani:
>
> 1. a dods file is not a netcdf file, although i think there are some 
> versions of ncdump that can work with dods. in short, you cant "get 
> the netcdf file" through opendap.
>
> 2. it appears that the original file is netcdf, so you may just want 
> to download the original file, in TDS you do that by enabling the 
> "fileserver" service. note that you are just downloading the file to 
> your local drive.
>
> 3. the metadata in the das and dds returns are equivalent to ncdump 
> -h, if thats all you want.
>
> 4. panolpy uses the netcdf-java library, so it should work with the 
> opendap endpoint.
>
> 5. recent versions of the netcdf C library can also work directly with 
> the file remotely, through opendap.
>
> john
>
> On 1/17/2012 8:50 AM, Estanislao Gonzalez wrote:
> > Hi,
> >
> > This is what a user tried to do and it didn't work:
> > ncdump
> > http://bmbf-ipcc-ar5.dkrz.de/thredds/dodsC/cmip5/output1/MPI-M/MPI-ESM-LR/rcp45/6hr/atmos/6hrPlev/r1i1p1/v20111006/psl/psl_6hrPlev_MPI-ESM-LR_rcp45_r1i1p1_2006010100-2006123118.nc 
> >
> > 2> nc_dump_log.txt
> >
> > The security is not the issue here as I can get it through the normal 
> > browser. AFAIK these are the supported OpenDAP formats:
> > .ascii - txt
> > .dods - some binary format (not NetCDF)
> > .dds - doesn't work with Gateway but it's just the metadata anyway
> > .das - doesn't work either for the same reason and I have no idea 
> > what it is (attribute values?)
> >
> > I've downloaded the dods file, as I was going to tell the user this 
> > is what he should be downloading, but I couldn't open it with NASAs 
> > Panoply. I guess that's because it's not a NetCDF stream, it's some 
> > OpenDAP half binary stream. I don't have the ncdump program so I 
> > can't test this (the one I could find was linked to the 4.1.1 library 
> > and AFAICT it won't work because of the security.
> >
> > Basically, the question would be: is it possible to get the NetCDF 
> > file via OpenDAP?
> > Should the user directly access the fileServer endpoint for that, 
> > even using ncdump?
> > Should *.nc.dods be the default endpoint for those cases?
> >
> > Any information on  the subject would be greatly appreciated :-)
> >
> > Thanks,
> > Estani


--
Estanislao Gonzalez

Max-Planck-Institut für Meteorologie (MPI-M)
Deutsches Klimarechenzentrum (DKRZ) - German Climate Computing Centre
Room 108 - Bundesstrasse 45a, D-20146 Hamburg, Germany

Phone:   +49 (40) 46 00 94-126
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