Re: [netcdf-java] Best practice for getting the initial (and/or final) time values of a Variable?

• To: James Adams - NOAA Affiliate <james.adams@xxxxxxxx>
• Subject: Re: [netcdf-java] Best practice for getting the initial (and/or final) time values of a Variable?
• From: Jon Blower <j.d.blower@xxxxxxxxxxxxx>
• Date: Wed, 13 Aug 2014 07:02:20 +0000

Hi James,

The ncWMS libraries contain some high-level calls that might help here. The 
uk.ac.rdg.resc.edal.cdm.CdmUtils class is the one you want:

NetcdfDataset nc = NetcdfDataset.open(“/path/to/my/netcdf/file”);
GridDatatype grid = CdmUtils.getGridDatatype(nc, “myvar”);
CoverageMetadata cm = CdmUtils.readCoverageMetadata(grid);
List<DateTime> dateTimes = cm.getTimeValues();

This gives a list of all the DateTime objects (these are from the joda-time 
library) in the time axis of the variable “myvar”. They will be referenced to a 
given Chronology (i.e. calendar system), which you can find through 
cm.getChronology().

The main snag is that your variable has to be fully georeferenced, otherwise 
readCoverageMetadata() won’t work. A common problem here is that the vertical 
axis isn’t always well defined in NetCDF files.

If you’re interested in this solution you can build a jar containing the above 
code:

svn checkout svn://svn.code.sf.net/p/ncwms/code/trunk ncwms
cd ncwms
ant jar-for-THREDDS

Hope this helps,
Jon


--
Dr Jon Blower,
Technical Director, Reading e-Science Centre,
MELODIES project coordinator,
School of Mathematical and Physical Sciences,
University of Reading
Tel: +44 118 378 5213
Email: j.d.blower@xxxxxxxxxxxxx

• Follow-Ups:
  • Re: [netcdf-java] Best practice for getting the initial (and/or final) time values of a Variable?
    • From: James Adams - NOAA Affiliate

• References:
  • [netcdf-java] Best practice for getting the initial (and/or final) time values of a Variable?
    • From: James Adams - NOAA Affiliate
  • Re: [netcdf-java] Best practice for getting the initial (and/or final) time values of a Variable?
    • From: Bob Simons - NOAA Federal
  • Re: [netcdf-java] Best practice for getting the initial (and/or final) time values of a Variable?
    • From: James Adams - NOAA Affiliate