[netcdf-java] How to create a structure in netcdf4

• To: netcdf-java@xxxxxxxxxxxxxxxx
• Subject: [netcdf-java] How to create a structure in netcdf4
• From: José Évora <jose.evora@xxxxxxxx>
• Date: Wed, 4 Nov 2015 07:54:45 +0000

Hi everyone,

I'm trying to create a structure (also know compounded type). In this email
I attach two different ways I've tried to do it and their respective error
message. This is the dependency I'm using

<dependency>
> <groupId>edu.ucar</groupId>
> <artifactId>netcdf4</artifactId>
> <version>LATEST</version>
> </dependency>


*1) NetCdfCreatorLite.java*

The execution throws a NullPointerException at

Structure otherVar = ncFile.addStructure(root, root.getParentStructure(),
> "Other", singletonList(other));


Exception in thread "main" java.lang.NullPointerException
> at ucar.nc2.NetcdfFileWriter.addStructure(NetcdfFileWriter.java:584)
> at org.mock.NetCdfCreatorLite.main(NetCdfCreatorLite.java:27)


*2) NetCdfCreatorLite2.java*

According to the java doc, the method addstructure shouldn't be used. Then,
in this second version, I uses a addVariable method to create the structure:

Structure otherVar = (Structure) ncFile.addVariable(root, "Other",
> STRUCTURE, singletonList(other));


The exeception given this time is:

Exception in thread "main" java.io.IOException: nc_put_vars: -49: NetCDF:
> Variable not found grpid=65536 objid=1
> at ucar.nc2.jni.netcdf.Nc4Iosp.writeCompoundData(Nc4Iosp.java:2895)
> at ucar.nc2.jni.netcdf.Nc4Iosp.writeData(Nc4Iosp.java:2839)
> at ucar.nc2.jni.netcdf.Nc4Iosp.writeData(Nc4Iosp.java:2721)
> at ucar.nc2.NetcdfFileWriter.write(NetcdfFileWriter.java:934)
> at ucar.nc2.NetcdfFileWriter.write(NetcdfFileWriter.java:918)
> at org.mock.NetCdfCreatorLite2.main(NetCdfCreatorLite2.java:46)


At line:

ncFile.write(otherVar, otherStructure);


If I comment the creation of structures, the application executes
perfectly. Even more, by only adding the addVariable of a structure line, I
get this exception, even though I only write the cityVar at line 50.

What is wrong? Can you please provide me with an example of use of the
structures?.

Best regards, thank you very much,

José Évora Gómez
Instituto Universitario SIANI
Universidad de Las Palmas de GC
@j_evora

Attachment: NetCdfCreatorLite.java
Description: Binary data

Attachment: NetCdfCreatorLite2.java
Description: Binary data

• Follow-Ups:
  • Re: [netcdf-java] How to create a structure in netcdf4
    • From: John Caron