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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
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Hi Sara, Here is a template Jupyter notebook that can be used to create netCDF gridded data that can be read into the IDV: https://gist.github.com/julienchastang/2129368a26ce0d85cff13cf0bc05cbf4 You will have to supply your own geophysical variables, etc. Good Luck, -Julien On Mon, Aug 22, 2016 at 11:48 AM, Don Murray (NOAA Affiliate) < don.murray@xxxxxxxx> wrote: > Hi Sara- > > It's obvious that you are creating a grid given your x/y/z dimensions, but > you do need to get the metadata right. I think the IDV may not like a time > unit of just "hours" - you might try "hours since 1970-01-01 00:00:00". > That's a limitation of the way the IDV handles time. And you might also > try Brian's suggestion of changing the dimension names. The IDV should not > need a Conventions global attribute - I would think that the underlying > netCDF-Java library should be able to handle some sort of default > convention that closely resembles the CF defaults. Maybe you could send a > sample file to Unidata and they could help you adjust the the metadata so > you'd just need the minimal amount. You shouldn't need to make such a file > CF compliant just to get it into the IDV. It was designed to handle a > variety of conventions (even none) - or at least it used to. > > Don Murray > > > On 8/22/16 9:20 AM, Julien Chastang wrote: > >> Hi Sara, >> >> There are a variety of problems here. For starters, there are no global >> attributes and metadata related to CF conventions. Moreover, the IDV is >> trying to find gridded data and can't, but is that really what you intend? >> I can't tell what kind of data these data are meant to be. I once wrote a >> blog entry on creating a CF compliant netCDF files with Python that can >> subsequently be read in to the IDV. >> >> http://www.unidata.ucar.edu/blogs/developer/entry/ipynb_cook >> books_to_create_cf >> http://nbviewer.jupyter.org/github/julienchastang/py-netcdf- >> cf-cookbooks/blob/master/traj.ipynb >> >> The example is for trajectory data, but you will be able to find many >> hints >> for the kind of data you wish to create, e.g., gridded data if that is >> what >> you intend. Again, make sure to follow CF conventions and checkout those >> NODC templates (described in the blog) for examples. >> >> Best, >> >> Unidata IDV Support >> >> On Mon, Aug 22, 2016 at 7:45 AM, Sara Loureiro Solla < >> sara.solla@xxxxxxxxxxxxx> wrote: >> >> Hello everyone! >>> >>> I am having trouble opening a *.nc file using IDV. The error I encounter >>> is " No gridded data found". I found some posts about the same problem in >>> the idvusers list, but I cannot find a proper solution. >>> >>> I create a nc file using python 2.7 and netCDF4.1.2.4 module. The >>> dimensions and the variables related to them are created this way: >>> >>> Dimensions: >>> dataout.createDimension('t', None) >>> dataout.createDimension('y', 361) >>> dataout.createDimension('x', 720) >>> dataout.createDimension('z', 1) >>> >>> Variables: >>> lat = self.dataout.createVariable('y', 'f4',( 'y',), zlib=True) >>> lat.units = 'degrees_north' >>> lon = self.dataout.createVariable('x', 'f4', ('x',), zlib=True) >>> lon.units = 'degrees_east' >>> time = self.dataout.createVariable('t', 'f4', ('t',), zlib=True) >>> time.units = 'hours' >>> time.calendar = 'gregorian' >>> vertical = self.dataout.createVariable('z','f4',('z',),zlib=True) >>> vertical.units = 'hPa' >>> vertical.positive = 'down' >>> >>> Variable filling: >>> lat[:] = np.arange(-90,90.5,.5) >>> lon[:] = np.arange(-180,180,.5) >>> time[:] = 80 >>> vertical[:] = 850 >>> >>> According to ncdump my file has the follow coordinate variable data: >>> t = 180 ; >>> z = 850 ; >>> y = -90, -89.5, -89, -88.5 ...... 85.5, 86, 86.5, 87, 87.5, 88, 88.5, 89, >>> 89.5, 90 ; >>> x = -180, -179.5, -179, ...... 178, 178.5, 179, 179.5 ; >>> >>> Any idea about what could lead to the "no gridded data found" error? >>> >>> Thank you very much! >>> Sara >>> >>> _______________________________________________ >> NOTE: All exchanges posted to Unidata maintained email lists are >> recorded in the Unidata inquiry tracking system and made publicly >> available through the web. Users who post to any of the lists we >> maintain are reminded to remove any personal information that they >> do not want to be made public. >> >> >> idvusers mailing list >> idvusers@xxxxxxxxxxxxxxxx >> For list information, to unsubscribe, visit: >> http://www.unidata.ucar.edu/mailing_lists/ >> >> > -- > Don Murray > NOAA/ESRL/PSD and CU-CIRES > 303-497-3596 > http://www.esrl.noaa.gov/psd/people/don.murray/ > -- Julien Chastang Scientific Software Developer Unidata-UCAR
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