Matplotlib X-axis timezone trouble

[Akira Li]

Peter Pearson <pkpearson at nowhere.invalid> writes:

> The following code produces a plot with a line running from (9:30, 0) to
> (10:30, 1), not from (8:30, 0) to (9:30, 1) as I desire.
>
> If I use timezone None instead of pacific, the plot is as desired, but
> of course that doesn't solve the general problem of which this is a
> much-reduced example.
>
> If I use timezone US/Central, I get the same (bad) plot.
>
> import matplotlib.pyplot as plt
> import datetime
> import pytz
> pacific = pytz.timezone("US/Pacific")
> fig = plt.figure()
> plt.plot([datetime.datetime(2014, 10, 7, 8, 30, tzinfo=pacific),
>           datetime.datetime(2014, 10, 7, 9, 30, tzinfo=pacific)],
>          [0,1], marker="o", color="green")
> fig.autofmt_xdate()
> plt.show()
>
> Does anybody know why this shift is occurring?  Is Matplotlib
> confused about what timezone to use in labeling the axis?  How
> would I tell it what timezone to use (preferably explicitly in
> the code, not in matplotlibrc)?
>

Your pytz usage is incorrect.

Don't pass a pytz tzinfo object to the datetime construtor directly, use
`.localize()` method instead. Read the note at the very beginning of
pytz docs http://pytz.sourceforge.net/