[netcdf-java] When Gridded datasets don't have GeoGrids...

[Ethan Davis]

Hi Chris,

For some reason, the zlev coordinate variable is not being recognized as 
a vertical coordinate axis. If I'm reading the CF spec correctly, the 
zlev variable needs a "positive" attribute with value "up" (or "down") 
or an "axis" attribute with the value "Z". I'm not able to test 
GribDataset with those changes at the moment but you could try to wrap 
the dataset with NcML that adds those attributes and see if that helps.

We'll have to look into improving those messages in parseInfo.

Ethan

Christopher Mueller wrote:
> All,
>
> I have an application which connects to OPeNDAP servers and allows the 
> user to subset the selected dataset and then retrieve a local copy of 
> the desired data. The application works well with most datasets that 
> are gridded – as long as the GridDataset contains GeoGrids. However 
> there are some datasets that don’t work for some reason, despite the 
> fact that they are DataType=Gridded.
>
> Here is the url for one such dataset:
> http://nomads.ncdc.noaa.gov:8085/thredds/dodsC/oceanwindsmon
>
> The line I’m using to generate a GridDataset (from which GeoGrids are 
> obtained) is:
> GridDataset gds = 
> (GridDataset)TypedDatasetFactory.open(thredds.catalog.DataType.GRID, 
> ncd, this, errlog);
>
> Where ncd is the NetcdfDataset pointing to the OPeNDAP data and errlog 
> is a StringBuffer for recording any errors (of which there never are any).
>
> The only information I can glean from stepping through my code comes 
> from the “parseInfo” field of the GridDataset. It is as follows (for 
> the dataset mentioned above):
> "GridDataset look for GeoGrids
> u(time, zlev, lat, lon) check CS zlev time lat lon: NOT complete
> v(time, zlev, lat, lon) check CS zlev time lat lon: NOT complete
> w(time, zlev, lat, lon) check CS zlev time lat lon: NOT complete
> "
>
> I’m hoping there’s another more “robust” method for generating a 
> GridDataset from a url as this is not the only dataset that this 
> occurs with, so a solution for this particular dataset isn’t of much use.
>
> Any help/advice is most appreciated.
>
> Thank you in advance,
> Chris
>
> -- 
> *Christopher Mueller* | Scientist
> Applied Science Associates
> 70 Dean Knauss Drive | Narragansett, RI 02882 USA
> p: +1 401-789-6224 | f: +1 401-789-1932
> e: cmueller at asascience.com | www.asascience.com
>
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> *
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-- 
Ethan R. Davis                                Telephone: (303) 497-8155
Software Engineer                             Fax:       (303) 497-8690
UCAR Unidata Program Center                   E-mail:    edavis at ucar.edu
P.O. Box 3000
Boulder, CO  80307-3000                       http://www.unidata.ucar.edu/
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