Re: [Matplotlib-users] Inverting a datetime / plot_date y-axis

[Benjamin R. <ben...@ou...>]

I would still consider this to be a bug, though. Gerd, could you please
file a bug report?

Cheers!
Ben Root

On Tue, Sep 16, 2014 at 7:45 AM, Joe Kington <jof...@gm...> wrote:

> A quick way to do this is ``ax.invert_yaxis()``  (and invert_xaxis() for
> the x-axis).  That way you preserve auto-scaling and don't wind up with
> manually set axis limits.
>
> What you did should have worked, but ``ymin`` and ``ymax`` are probably
> datetime objects.  ``ylim`` isn't smart enough to convert them to the
> datetime units that matplotlib uses internally.
>
> Hope that helps!
> -Joe
>
> On Tue, Sep 16, 2014 at 4:00 AM, Gerd Wellenreuther <
> Ger...@xf...> wrote:
>
>> Dear all,
>>
>> I hope some of you could help me out. I am currently trying to generate
>> some timetables using matplotlib.pyplot.plot_date, having the time-axis
>> on the y-axis. Typically, one would like to read these plots from top to
>> bottom, from older to newer items (future on the bottom). Unfortunately,
>> the default enumeration of the y-axis is the other way around, and it
>> resists my attempts to invert its direction e.g. by changing limits
>> using matplotlib.pyplot.ylim (Traceback below). I found a quite old
>> entry in stackoverflow which is most probably outdated, at least the
>> proposed solution did not work for me...
>> (
>> http://stackoverflow.com/questions/5804969/displaying-an-inverted-vertical-date-axis
>> ).
>>
>> Since the longish traceback seems to try to tell me I did not understand
>> some kind of important - even trivial - point about those datetime-axis
>> maybe some of you came about this problem before?
>>
>> Thanks, Gerd
>>
>> P.S.: Traceback after trying to use something like
>> "matplotlib.pyplot.ylim(ymax,ymin)":
>> > Traceback (most recent call last):
>> >   File "C:\Users\gwellenr\Desktop\Test_Sabine\Plot_csv.py", line 187,
>> > in <module>
>> >     matplotlib.pyplot.savefig(save_path+'test.png')
>> >   File "C:\Python27\lib\site-packages\matplotlib\pyplot.py", line 561,
>> > in savefig
>> >     return fig.savefig(*args, **kwargs)
>> >   File "C:\Python27\lib\site-packages\matplotlib\figure.py", line
>> > 1421, in savefig
>> >     self.canvas.print_figure(*args, **kwargs)
>> >   File "C:\Python27\lib\site-packages\matplotlib\backend_bases.py",
>> > line 2220, in print_figure
>> >     **kwargs)
>> >   File
>> > "C:\Python27\lib\site-packages\matplotlib\backends\backend_agg.py",
>> > line 505, in print_png
>> >     FigureCanvasAgg.draw(self)
>> >   File
>> > "C:\Python27\lib\site-packages\matplotlib\backends\backend_agg.py",
>> > line 451, in draw
>> >     self.figure.draw(self.renderer)
>> >   File "C:\Python27\lib\site-packages\matplotlib\artist.py", line 55,
>> > in draw_wrapper
>> >     draw(artist, renderer, *args, **kwargs)
>> >   File "C:\Python27\lib\site-packages\matplotlib\figure.py", line
>> > 1034, in draw
>> >     func(*args)
>> >   File "C:\Python27\lib\site-packages\matplotlib\artist.py", line 55,
>> > in draw_wrapper
>> >     draw(artist, renderer, *args, **kwargs)
>> >   File "C:\Python27\lib\site-packages\matplotlib\axes.py", line 2086,
>> > in draw
>> >     a.draw(renderer)
>> >   File "C:\Python27\lib\site-packages\matplotlib\artist.py", line 55,
>> > in draw_wrapper
>> >     draw(artist, renderer, *args, **kwargs)
>> >   File "C:\Python27\lib\site-packages\matplotlib\axis.py", line 1091,
>> > in draw
>> >     ticks_to_draw = self._update_ticks(renderer)
>> >   File "C:\Python27\lib\site-packages\matplotlib\axis.py", line 945,
>> > in _update_ticks
>> >     tick_tups = [t for t in self.iter_ticks()]
>> >   File "C:\Python27\lib\site-packages\matplotlib\axis.py", line 889,
>> > in iter_ticks
>> >     majorLocs = self.major.locator()
>> >   File "C:\Python27\lib\site-packages\matplotlib\dates.py", line 802,
>> > in __call__
>> >     self.refresh()
>> >   File "C:\Python27\lib\site-packages\matplotlib\dates.py", line 820,
>> > in refresh
>> >     self._locator = self.get_locator(dmin, dmax)
>> >   File "C:\Python27\lib\site-packages\matplotlib\dates.py", line 896,
>> > in get_locator
>> >     raise ValueError('No sensible date limit could be found in the '
>> > ValueError: No sensible date limit could be found in the
>> AutoDateLocator.
>>
>>
>>
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