Errors with code plotting crashing kernel in sec_4_Regridding.ipynb

[harley-kelly]

When plotting regridded data, the kernel dies. Below error message is shown:

This link is the 'click for more info': https://github.com/microsoft/vscode-jupyter/wiki/Kernel-crashes

The log shows: '[error] Disposing session as kernel process died ExitCode: undefined, Reason: ' and does not define the reason.