mplot3d and daspect

Benjamin Root <ben.root@...83...> writes:

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/pbaspectAfter building
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

···

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- 3jVuOyHyqGOMbxhyh7iT0rNAH6kLmebB@...1455...> wrote:

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

···

On Fri, Nov 2, 2012 at 3:18 AM, Alexandr <o.pischanskyy@…287…> wrote:

Benjamin Root <ben.root@…83…> writes:

On Thu, Jun 9, 2011 at 10:13 AM, Benjamin Root <ben.root ou.edu> wrote:

On Thu, Jun 9, 2011 at 6:25 AM, Richard Hofmeister <richard.hofmeister- > > 3jVuOyHyqGOMbxhyh7iT0rNAH6kLmebB@…1455…> 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/pbaspectAfter building
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(-x2 -
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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Matplotlib-users mailing list

Matplotlib-users@…83…

https://lists.sourceforge.net/lists/listinfo/matplotlib-users

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