The error associated with layer_sum/layer_mean tile plots for unconventional 3D variables

[dkang2]

Describe the bug
The layer_sum/mean stats for VERDIv2.1.6 are nice additions, it works well with normal variables (col, row, layer, time), but when they are used for some unconventional variables such as CROPF and TREEF in the following file, it produced an error message when the layers range is selected. It works well with LANDUSEF, another similar variable.

To Reproduce
Steps to reproduce the behavior:

1. verdi -f /work/MOD3DEV/dkj/Verdi/example_files/beld4_CMAQ12KM_2011.nc
2. Click on "CROPF (Percent)[3]
3. Click on "Use Layer Range", and choose any layer range (but if all layers are selected, it works), as show in the plot:
4. See error
   

The command line message:

024.10.31 14:19:49.192 [AWT-EventQueue-0] ERROR anl.verdi.core.VerdiApplication - Error while evaluating formula
java.lang.NullPointerException: Cannot invoke "ucar.nc2.dataset.CoordinateAxis.getDimension(int)" because the return value of "ucar.nc2.dataset.NetcdfDataset.findCoordinateAxis(String)" is null
at anl.verdi.loaders.GridNetcdfReader.getValues(GridNetcdfReader.java:68) ~[?:?]
at anl.verdi.loaders.GridNetcdfReader.getValues(GridNetcdfReader.java:1) ~[?:?]
at anl.verdi.formula.FormulaVariable.evaluate(FormulaVariable.java:78) ~[?:?]
at anl.verdi.formula.DefaultFormula.readData(DefaultFormula.java:86) ~[?:?]
at anl.verdi.formula.DefaultFormula.evaluate(DefaultFormula.java:275) ~[?:?]
at anl.verdi.core.VerdiApplication.evaluateFormula(VerdiApplication.java:446) ~[?:?]
at anl.verdi.core.VerdiApplication.evaluateFormula(VerdiApplication.java:396) ~[?:?]
at anl.verdi.plot.gui.action.FastTilePlot.actionPerformed(FastTilePlot.java:42) ~[?:?]
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1972) ~[?:?]
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2314) ~[?:?]
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:407) ~[?:?]
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262) ~[?:?]
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279) ~[?:?]
at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:297) ~[?:?]
at java.awt.Component.processMouseEvent(Component.java:6621) ~[?:?]
at javax.swing.JComponent.processMouseEvent(JComponent.java:3398) ~[?:?]
at java.awt.Component.processEvent(Component.java:6386) ~[?:?]
at java.awt.Container.processEvent(Container.java:2266) ~[?:?]
at java.awt.Component.dispatchEventImpl(Component.java:4996) ~[?:?]
at java.awt.Container.dispatchEventImpl(Container.java:2324) ~[?:?]
at java.awt.Component.dispatchEvent(Component.java:4828) ~[?:?]
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4948) ~[?:?]
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4575) ~[?:?]
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4516) ~[?:?]
at java.awt.Container.dispatchEventImpl(Container.java:2310) ~[?:?]
at java.awt.Window.dispatchEventImpl(Window.java:2780) ~[?:?]
at java.awt.Component.dispatchEvent(Component.java:4828) ~[?:?]
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:775) ~[?:?]
at java.awt.EventQueue$4.run(EventQueue.java:720) ~[?:?]
at java.awt.EventQueue$4.run(EventQueue.java:714) ~[?:?]
at java.security.AccessController.doPrivileged(AccessController.java:400) [?:?]
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87) ~[?:?]
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:98) ~[?:?]
at java.awt.EventQueue$5.run(EventQueue.java:747) ~[?:?]
at java.awt.EventQueue$5.run(EventQueue.java:745) ~[?:?]
at java.security.AccessController.doPrivileged(AccessController.java:400) [?:?]
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87) [?:?]
at java.awt.EventQueue.dispatchEvent(EventQueue.java:744) [?:?]
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203) [?:?]
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124) [?:?]
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113) [?:?]
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109) [?:?]
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) [?:?]
at java.awt.EventDispatchThread.run(EventDispatchThread.java:90) [?:?]

[yadongxuEPA]

Tested with VERDI_2.1.6_linux64_20241120.tar.gz on Atmos, confirmed that this issue has resolved.