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

[Gerd W. <Ger...@xf...>]

Just posted some small code under 
https://github.com/matplotlib/matplotlib/issues/3522

I guess the formatting is not up to standards, but I did not find 
another way to attach the code...

Cheers, Gerd

On 16.09.2014 15:29, Benjamin Root wrote:
> Perhaps something is odd with the date values you have? Can you make 
> an SSCCE (sscce.org <http://sscce.org>)that demonstrates the problem? 
> There is definitely some sort of bug at play here.
>
> Cheers!
> Ben Root
>
> On Tue, Sep 16, 2014 at 9:20 AM, Gerd Wellenreuther 
> <Ger...@xf... <mailto:Ger...@xf...>> wrote:
>
>     Tried this before, I think, here is the traceback (it is kind of
>     different) - maybe it tells some of you where to look at IF this
>     should really be a bug:
>
>
>>     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.
>
>     Cheers, Gerd
>
>
>     On 16.09.2014 13:45, Joe Kington 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... <mailto: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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>
>
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