problem with netCDF4 OpenDAP
Tom P
werotizy at freent.dd
Fri Aug 14 03:18:54 EDT 2015
On 08/13/2015 05:55 PM, Jason Swails wrote:
>
>
> On Thu, Aug 13, 2015 at 6:32 AM, Tom P <werotizy at freent.dd
> <mailto:werotizy at freent.dd>> wrote:
>
> I'm having a problem trying to access OpenDAP files using netCDF4.
> The netCDF4 is installed from the Anaconda package. According to
> their changelog, openDAP is supposed to be supported.
>
> netCDF4.__version__
> Out[7]:
> '1.1.8'
>
> Here's some code:
>
> url =
> 'http://www1.ncdc.noaa.gov/pub/data/cmb/ersst/v3b/netcdf/ersst.201507.nc'
> nc = netCDF4.Dataset(url)
>
> I get the error -
> netCDF4/_netCDF4.pyx in netCDF4._netCDF4.Dataset.__init__
> (netCDF4/_netCDF4.c:9551)()
>
> RuntimeError: NetCDF: file not found
>
>
> However if I download the same file, it works -
> url = '/home/tom/Downloads/ersst.201507.nc <http://ersst.201507.nc>'
> nc = netCDF4.Dataset(url)
> print nc
> . . . .
>
> Is it something I'm doing wrong?
>
>
> Yes. URLs are not files and cannot be opened like normal files.
> netCDF4 *requires* a local file as far as I can tell.
>
> All the best,
> Jason
>
> --
> Jason M. Swails
> BioMaPS,
> Rutgers University
> Postdoctoral Researcher
Thanks for the reply but that is not what the documentation says.
http://unidata.github.io/netcdf4-python/#section8
"Remote OPeNDAP-hosted datasets can be accessed for reading over http if
a URL is provided to the netCDF4.Dataset constructor instead of a
filename. However, this requires that the netCDF library be built with
OPenDAP support, via the --enable-dap configure option (added in version
4.0.1)."
and for the Anaconda package -
http://docs.continuum.io/anaconda/changelog
"2013-05-08: 1.5.0:
Highlights:
updates to all important packages: python, numpy, scipy, ipython,
matplotlib, pandas, cython
added netCDF4 (with OpenDAP support) on Linux and MacOSX"
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