Robust Units Handeling

[jhamman]

Current, RVIC is using an ad hoc input/output units scheme, checking for a few known combinations of unit strings (e.g. 'mm', 'kg m-2 s-1', etc). There are a few Python projects that have wrapped the UDUNITS library that support conversion of a range of units.

Two packages that come to mind:

• udinitspy
• cfunits-python

One of these should be included in read_forcings.py and history.py to handle the units conversion that is currently done in a more sophisticated way.

CC: @bartnijssen, @mrstu
related: #55

[jhamman]

@mrstu, have you used either of these projects?

[ocefpaf]

@jhamman Scitools iris provides a python wrapper for udunits that is now available as a stand alone module called (https://github.com/SciTools/cf_units).

cf-units is similar to cfunits-python python, but better maintained, lager community, and easier to install (no hard coded path, etc). We have conda binaries for Win, OSX and, Linux. (Sorry no python 3 yet!)

Check this out for some examples.

[jhamman]

Thanks @ocefpaf -

cf_units looks like it will be the best options moving forward. Once there is Python 3 support, I'll give it a try here.

related: SciTools/cf-units#22