Re: [Matplotlib-users] mplot3d and daspect

On Fri, Nov 2, 2012 at 3:18 AM, Alexandr <o.p...@gm...> wrote:

> Benjamin Root <ben.root@...> writes:
>
> >
> >
> > On Thu, Jun 9, 2011 at 10:13 AM, Benjamin Root <ben.root <at> ou.edu>
> wrote:
> >
> >
> >
> >
> > On Thu, Jun 9, 2011 at 6:25 AM, Richard Hofmeister <richard.hofmeister-
> 3jV...@pu...> wrote:
> > Hello mplot3d specialists,I would like to change the aspect ratio of the
> 3d
> axes similar to matlab's functionality with daspect() or the
> 'dataaspectratio'
> property of 3d-axes.In the end, the x-y-plane should be non-square due to
> different lengths (not range) of the x and y axis (i know that i can use
> the
> aspect property of the axes to set the x-z/y-z aspect ratio).There is also
> the
> package "scitools", which provides all the matlab-3d functions including
> daspect
> via a VTK-backend; that would be my next try.For the simple 3d-plotting
> without
> fancy shading, i would like to stick to mplot3d:
> >
> >
> >
> > Is it possible to change the axis lengths/aspect ratios
> independently?Richard
> >
> >
> >
> >
> > Richard,Good question.  I have never thought about such a feature for
> mplot3d.  Looking back at the code, it does not appear to be feasible to
> do in
> its current state, as the code seems to assume that the 3d grid is a
> constructed
> from a unit cube.  However, I will see if I can add aspect multipliers to
> the
> point calculation and get arbitrary aspects.  Maybe I can get that feature
> added
> into the upcoming 1.1.0 release.Ben Root
> >
> >
> >
> >
> > Richard,I took a look at how this might be implemented.  There would
> have to
> be some extra work to make the plots look right when experiencing changes
> in
> aspect.  I first tried an implementation of just the plot box aspect ratio
> (pbaspect) as a member variable of the axes object.  It will probably turn
> into
> a property so that I can link it with a daspect value.  Also, the values
> should
> be normalized to 1, unless you want to see some interesting
> shrinkage/growth of
> your plot area.Try my branch here:
> https://github.com/WeatherGod/matplotlib/tree/mplot3d/pbaspectAfterbuilding
> that branch, try the following script (shamelessly adapted from some
> Matlab help
> pages for pbaspect and daspect).import matplotlib.pyplot as pltfrom
> mpl_toolkits.mplot3d import Axes3Dimport numpy as npfig = plt.figure()ax =
> fig.gca(projection='3d')x, y = np.mgrid[-2:2:.2, -2:2:.2]z = x *
> np.exp(-x**2 -
> y**2)
> >
> > ax.plot_surface(x, y, z, rstride=1, cstride=1)ax.pbaspect = [1.0, 1.0,
> 0.25]plt.show()While this will squash the z-axis nicely, it does not force
> the
> z-ticks to be pruned, so it gets a little ugly.  However, the axis ticks
> can be
> changed manually.  Also, with some of my other changes coming soon, it
> should be
> possible for the Axes3D object to automatically adjust the spacing of the
> tick
> labels so that it is not impacted by the changes in aspect ratio in the
> perpendicular direction (i.e. - the x and y tick labels are closer to the
> axis
> due to the z-axis scaling).Keep an eye on that branch as I work to improve
> this
> feature, and feel free to contribute to it as well!Ben Root
> >
> >
> >
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>
>
> Hello!
>
> I am looking for a tool like pbaspect. The only question is how to
> implement it
> into matplotlib? Do you have a step by step instruction?
>
> Thank you.
> Regards,
> Alexandr
>
>
I guess there has been enough interest in this feature that I probably
should devote some time to correctly implementing it.  I'll see what I can
do!

Ben Root