Matplotlib X-axis timezone trouble

[Peter Pearson]

On Tue, 30 Jun 2015 04:03:57 +0200, Laura Creighton <lac at openend.se> wrote:
> In a message of 30 Jun 2015 00:56:26 +0000, Peter Pearson 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)?
[snip]
>
> I know that your problem is that all your times are in UTC, even
> though you do not want this.  I had this too.  I forget what I did.

Actually, UTC is very helpful in this project, which has to
deal with timestamped data from various timezones.  After I finally
stumbled upon datetime's astimezone() method, things seemed to be
going smoothly . . .

> I do not know if this solution from stackoverflow.com will work for
> you -- it is definitely different from what I did, but that does
> not in any way make it wrong.  Try and see?  and report back?
>
> http://stackoverflow.com/questions/4485607/matplotlib-plot-date-keeping-times-in-utc-even-with-custom-timezone

Thanks for the pointer.  I'll report back.


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