Home >> Forums >> Error tracking variable

Error tracking variable

Hi all,
I have been using a HYCOM dataset adapted for use with the 2D Mercator configuration in Ichthyop. The simulation seems to run fine but I am unable to track variables, temperature (T) in this case. I get the following error when I run it through the console:
ichthyop[warning] Error tracking variable T. The variable will no longer be recorded in the NetCDF output file. | java.lang.NullPointerException

I'm not sure what the issue is, the spelling of the desired variable seems to be fine in the variable tracking function in output options. I have attached the rest of the console output as well as the NetCDF and cfg files. Any help with this would be hugely appreciated.




Ichthyop version: 
Ichthyop 3.3alpha
Hydrodynamic dataset: 
Java version: 
Java SE 8
Operating system: 
Windows 7

Hi Ryan,

There was indeed a small bug in the Mercator2D.java class, which prevented the tracking of data.

It is now corrected and provided in the 3.3.3 version (see http://www.ichthyop.org/downloads/ichthyop-333).

The tracked variables should be read in a "gridT" file (see the "gridT file pattern" parameter of the enclosed configuration file).

Furthermore, I suggest that you correct your input files so that the NetCDF _FillValue appears. Indeed, with your file, Ichthyop considers that all the points are wet points, which is not the case. See the attributes of Netcdf file enclosed


Hi Nicholas,
Many thanks for your help with this, it is hugely appreciated. Temperature tracking works well in the newer version. I have also included the NetCDF _FillValue you suggest.