Re: [Matplotlib-users] Colorbar for pcolor plot

[Ryan M. <rm...@gm...>]

On Wed, May 20, 2009 at 10:04 AM, John Hunter <jd...@gm...> wrote:

> On Wed, May 20, 2009 at 9:53 AM, Ryan May <rm...@gm...> wrote:
>
> > Thanks for the full example, but if you carefully read the exception, it
> was
> > telling you the problem. :)  plot1 here is an axes object, which does not
> > have a colorbar() method.  Instead, you should change that to:
> >
> > plt.colorbar()
> >
> > Assuming everything else was working, you should be good to go with this
> > change.
> >
>
> It looks like Markus is trying to use the API, so rather than suggest
> the pyplot colorbar method, I suggest using the figure instance
> method.  Markus the pyplot method plt.colorbar is a thin wrapper
> around the figure method fig.colorbar -- see also:
>
>
> http://matplotlib.sourceforge.net/faq/usage_faq.html#matplotlib-pylab-and-pyplot-how-are-they-related
>
>
> http://matplotlib.sourceforge.net/api/figure_api.html#matplotlib.figure.Figure.colorbar
>
> It may be a good idea and refer to the return value of fig.add_subplot
> as "ax" or something that, rather than "plot1" because add_subplot
> returns an Axes instance and thus ax is a better mnemonic; see
>
>
> http://matplotlib.sourceforge.net/api/figure_api.html#matplotlib.figure.Figure.add_subplot
>
> So I suggest something like::
>
>    fig = plt.figure()
>
>    ax1 = fig.add_subplot(231,aspect='equal')
>    ax1.pcolor(xsr)
>    ax1.axis([0, 127, 0, 127])
>    fig.colorbar()


Except that it won't work like that. :) (I actually tried that the first
time) You need to give Figure.colorbar() the mappable as the first
argument.  So this would then become:

    ax1 = fig.add_subplot(231,aspect='equal')
    pc = ax1.pcolor(xsr)
    ax1.axis([0, 127, 0, 127])
    fig.colorbar(pc)

Ryan

-- 
Ryan May
Graduate Research Assistant
School of Meteorology
University of Oklahoma
Sent from Norman, Oklahoma, United States