Re: [Matplotlib-users] Bug in colorbar()

[Eric F. <ef...@ha...>]

On 2012/07/29 5:13 AM, Jeffrey Spencer wrote:
> Eric,
>
> Normalize appears to be working correctly and as you stated above but
> when passed into contourf appears to have inconsistent results not
> following the docstring by allowing the value to change.
>
> Quick examples:
>
> X, Y = meshgrid(arange(20),arange(20))
> Z = arange(20*20)
> Z = Z.reshape(20,20)
> norm = colors.Normalize(vmin=200,vmax=None)
> print norm.vmin
> fig = figure(10)
> ax = fig.add_subplot(111)
> surf = ax.contourf(X,Y,Z, 100, cmap=matplotlib.cm.jet, norm = norm)
>
> This vmin has no effect where if you pass in:
>
> X, Y = meshgrid(arange(20),arange(20))
> Z = arange(20*20)
> Z = Z.reshape(20,20)
> norm = colors.Normalize(vmin=200,vmax=Z.max())
> print norm.vmin
> fig = figure(10)
> ax = fig.add_subplot(111)
> surf = ax.contourf(X,Y,Z, 100, cmap=matplotlib.cm.jet, norm = norm)
>
> it has the desired effect.
>
> Let me know if this is correct or I'm missing something here.
>
> Cheers,
> Jeff

You are correct.  Contour and contourf are respecting vmin, vmax that 
have been set in the norm only if both have been set, so that it is 
fully scaled.  I think that changing this to respect a single preset 
vmin or vmax would be reasonable.

Eric