Time-height plotting

[nguy]

Currently Py-ART does not support time-height plots it seems. The VPT (vertically-pointing) plot function plots the abscissa as distance ( I assume for a scanning type?). I would suggest modifying the RadarDisplay.plot_vpt to accept (or access) a time variable and format accordingly. Maybe use of a keyword?

This topic had some discussion in Issue #364 .

One potential issue would be to make sure that time was represented consistently.

[nguy]

I found some time conversion utilities in pyart.util.datetime_utils.py, but cannot find an instance of these being used in the package.

I think adding a conversion to Epoch time here would be useful in the future when potentially combining radar instances.

[jjhelmus]

@nguy Sounds like a great suggestion. The current VPT plots do not properly represent gaps in time or even indicate the timing of the measurement. I'll have a look at #453 later today and make some comments/suggestions.

[jjhelmus]

Closed by PR #453