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[netCDFJava #BDR-563250]: Issue reading/writing with OPENDAP

Ann,

What version of netcdf-java are you using? I made a mistake based on what I 
thought would happen, but hadn't run your example code. When I run your 
example, with netcdf-java 4.6.1, your original URL ending in '.nc' works fine 
for me.

There is one problem where I get an exception at line 63 because you are taking 
a variable from the Opendap dataset and passing it to ncwriter.write() for the 
local dataset; you can't do that, you need to create a new Variable for the 
local dataset.

Ryan

> Hi Ryan,
> 
> I used the URL (String 
> inputfile="http://convection.meas.ncsu.edu:8080/thredds/dodsC/prism/daily/tmin/PRISM_tmin_stable_4kmD1_20110515.nc.dods";;)
>  that you had provided and unfortunately I got the below error when I try to 
> open the file using either openDataset() and openFile().
> I had checked and the server is not down.
> 
> opendap.dap.DAP2Exception: HTTP/1.1 404 Not Found: 
> http://convection.meas.ncsu.edu:8080/thredds/dodsC/prism/daily/tmin/PRISM_tmin_stable_4kmD1_20110515.nc.dods.dds
> at opendap.dap.DConnect2.openConnection(DConnect2.java:273)
> at opendap.dap.DConnect2.getDDS(DConnect2.java:584)
> at opendap.dap.DConnect2.getDDS(DConnect2.java:557)
> at ucar.nc2.dods.DODSNetcdfFile.<init>(DODSNetcdfFile.java:241)
> at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
> at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
> at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
> at java.lang.reflect.Constructor.newInstance(Unknown Source)
> at 
> ucar.nc2.dataset.NetcdfDataset.openDodsByReflection(NetcdfDataset.java:1036)
> at ucar.nc2.dataset.NetcdfDataset.acquireDODS(NetcdfDataset.java:986)
> at ucar.nc2.dataset.NetcdfDataset.openOrAcquireFile(NetcdfDataset.java:712)
> at ucar.nc2.dataset.NetcdfDataset.openDataset(NetcdfDataset.java:426)
> at ucar.nc2.dataset.NetcdfDataset.openDataset(NetcdfDataset.java:409)
> at ucar.nc2.dataset.NetcdfDataset.openDataset(NetcdfDataset.java:394)
> at ucar.nc2.dataset.NetcdfDataset.openDataset(NetcdfDataset.java:381)
> at testzone.Opendapexample.main(Opendapexample.java:47)
> 
> I am not sure how a .dds is getting added to the end of the string.  How are 
> you opening the file to read the contents?
> Also I don’t want to download the PRISM data. I want to copy the data to 
> another new netcdffile.
> 
> Thanks for the help!
> Ann
> 
> -----Original Message-----
> From: Unidata netCDF Java Support [mailto:address@hidden]
> Sent: Monday, May 11, 2015 5:35 PM
> To: Ann Smittu Joseph
> Cc: address@hidden
> Subject: [netCDFJava #BDR-563250]: Issue reading/writing with OPENDAP
> 
> Ann,
> 
> Thanks for the detailed bug report. In order to read the dataset using 
> opendap support within NetcdfDataset, the URL needs to end with '.dods'. So 
> in your case, the URL should be:
> 
> String 
> inputfile="http://convection.meas.ncsu.edu:8080/thredds/dodsC/prism/daily/tmin/PRISM_tmin_stable_4kmD1_20110515.nc.dods";;
> 
> (This is the same URL as the "Get Binary" button on the Opendap HTML page.)
> 
> Using this new URL, I'm able to download the data. Let me know if that's not 
> the case for you.
> 
> Ryan
> 
> > Hi,
> >
> > I have an issue trying to read and write data to netcdf using OPENDAP.
> > I am not sure if the issue is at the server or in my code. If I save
> > the "PRISM.....nc" in my local system and then use openFile(). The
> > program runs fine.
> >
> > If I try to read the data using OPENDAP url and openFile(), I get the
> > error:
> >
> > Exception in thread "main" java.lang.ClassCastException:
> > ucar.nc2.dods.DodsV cannot be cast to
> > ucar.nc2.iosp.netcdf3.N3header$Vinfo
> > at ucar.nc2.iosp.netcdf3.N3iosp.writeData(N3iosp.java:695)
> > at ucar.nc2.NetcdfFileWriter.write(NetcdfFileWriter.java:931)
> > at testzone.Opendapexample.main(Opendapexample.java:66)
> >
> > If I try to read the data using OPENDAP url and openDataset, I get the 
> > error:
> > Exception in thread "main" java.lang.NullPointerException at
> > ucar.nc2.iosp.netcdf3.N3iosp.writeData(N3iosp.java:717)
> > at ucar.nc2.NetcdfFileWriter.write(NetcdfFileWriter.java:931)
> <SNIP>
> >
> > Ann
> 
> 
> Ticket Details
> ===================
> Ticket ID: BDR-563250
> Department: Support netCDF Java
> Priority: Normal
> Status: Closed
> 
> 


Ticket Details
===================
Ticket ID: BDR-563250
Department: Support netCDF Java
Priority: Normal
Status: Closed