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[netCDFJava #ZTS-930267]: [netCDF-Java #FNP-784202] netCDF Java - Writing a Subsetted OPeNDAP Dataset to a Local File

Hi Chris,

> I have since been informed that subsetting using NcML is probably not very
> useful for my application and that I should pursue �direct subsetting� via
> the query url.  Along this line � I have encountered another problem that
> I was hoping you could help me with.
> 
> I am attempting to create a local nc file which is a subset of data on the
> �motherload� server.  Specifically, my data url is:
> 
> http://motherlode.ucar.edu:8080/thredds/dodsC/modelsNc/NCEP/OCEAN/Global_5x2p5deg/OCEAN_Global_5x2p5deg_20070828_1200.nc?lat[0:1:19],lon[0:1:39],u_sfc[0:1:0][0:1:19][0:1:39],v_sfc[0:1:0][0:1:19][0:1:39]
> 
> This URL works just fine both in the toolsUI as well as in my application
> (very basic right now).  The problem arrises when I go to write the file
> to a local nc file.  I am receiving an InvalidRangeException error which
> I don�t quite understand.  I�m not manipulating or changing the data in
> any way, though I am �testing� the NetcdfFile object to ensure that there
> is information there.  The code (everything that�s being called) and error
> are attached:

The problem is that the URL above is an OPeNDAP dataset URL so you are getting 
back an OPeNDAP encoding of the data rather than a netCDF file. If you go to 
the catalog that lists the above dataset:

http://motherlode.ucar.edu:8080/thredds/catalog/modelsNc/NCEP/OCEAN/Global_5x2p5deg/catalog.html

and click down to a dataset, you will see that the dataset is accessible 
through OPeNDAP, WCS, and as an HTTP download. Which means you can get the 
entire dataset using the HTTP download or you can access subsets of the dataset 
if you have a WCS client.

If you start at our top level catalog 
(http://motherlode.ucar.edu:8080/thredds/catalog.html), you can browse down to 
some of our other model data and see another type of access called the netCDF 
Subset Service (ncSS). That is a simpler interface for accessing dataset 
subsets that might be of interest to you. Here's the catalog for a model 
collection that is available with ncSS: 
http://motherlode.ucar.edu:8080/thredds/catalog/fmrc/NCEP/GFS/Alaska_191km/files/catalog.html

If you are interested in the OCEAN data and the ncSS, I can check into why that 
combination isn't available.

Hope this helps. Let me know if you have other questions.

Ethan

Ticket Details
===================
Ticket ID: ZTS-930267
Department: Support netCDF Java
Priority: Normal
Status: Open