On Thu, Jul 21, 2011 at 7:46 PM, gary ruben <gru...@bigpond.net.au> wrote:
> Hi Ben,
> Comments inline...
>
> On Fri, Jul 22, 2011 at 1:31 AM, Benjamin Root <ben.r...@ou.edu> wrote:
> >
> >
> > On Thu, Jul 21, 2011 at 1:10 AM, gary ruben <gary.ru...@gmail.com>
> wrote:
> >>
> >> I'm trying to make a surface plot using the latest version of mplot3d
> >> from the git trunk and I have a couple of questions. The attached
> >> image is close to what I would like. The associated plot command I am
> >> using is
> >>
> >> ax.plot_surface(X, Y, Z, rstride=1, cstride=1, alpha=0.8, shade=True,
> >> cmap=plt.cm.summer,
> >> color='k',
> >> facecolors='k',
> >> lightsource = LightSource(azdeg=0, altdeg=0),
> >> )
> >>
> >> 1. Is there support now to automatically annotate the axis so that a
> >> multiplier is added, as occurs in 2D plots, or should I do this
> >> manually by rescaling the data for the moment?
> >
> > Yes, offset text is now automatic and should activate in similar manner
> as
> > it does for regular 2D axis formatters. You were one order of magnitude
> off
> > from automatically triggering it. Also, I should note that it might be
> > better to use "ax = fig.gca(projection='3d')" instead of "ax =
> Axes3D(fig)"
> > because the former will leave more of a margin, which would allow the
> offset
> > text to be fully visible.
>
> Thanks. That's actually what I am doing but I cropped the output image
> before attaching it.
>
> > If you want the full figure area, then you may
> > need to fiddle with the ax.zaxis._axinfo['label']['space_factor'] to
> bring
> > it and the axis label closer to the axis.
>
> Thanks. That's useful to know.
>
> > The odd thing that I am encountering right now while investigating your
> > problem is that I can't seem to force the use of the offset. It could
> just
> > be that I am doing it wrong, but I will look closer.
>
> Yes, I had set 'axes.formatter.limits' : (-2, 2) hoping to trigger it
> - I guess that's what you tried.
>
> >> 2. Currently, it doesn't appear possible to shade the surface patches
> >> according to just a base facecolor and their orientation to a light
> >> source. Do I have to define a new colormap with a constant/single
> >> colour to achieve this?
> >
> > Looking over the plot_surface code, this appears to be the case, however,
> > looking back over the LightSource code, I believe it might be possible to
> > update plot_surface to operate on situations where no cmap is specified.
> I
> > will take a look today at that possibility and see if I can get it out
> for
> > the v1.1.0 release.
>
> That would be great - it is a very good way to visualize a surface so
> it should be made as simple as possible.
>
> >> 3. I have set alpha=0.8 to allow the wireframe lines to show through a
> >> little. When shade=False, the wireframe is visible but I lose
> >> orientation-based shading. Is there a way to overlay the wireframe
> >> properly when shade=True?
> >>
> >
> > In plot_surface, when shade=True, it appears that both the facecolors and
> > the edgecolors are set to the same colors. The only reason why the lines
> > show up when you set transparency is that that alpha value is applied
> only
> > to the faces and not the edges. Specifically, the logic is as follows:
> >
> > if fcolors is specified, then set that color for both facecolor and
> > edgecolor.
> > Else, if a cmap is specified, then give the polygon collection the data,
> > limits and norm it needs to determine color itself.
> > Else, then use the value of "color" to specify only the facecolors.
> >
> > I think the first branch of this logic is a bit wonky.
>
> I agree, since fcolors must be specified in order to trigger the
> lightsource-based shading.
>
> > I am inclined to
> > make a small change that would only set the edgecolors if 'edgecolors'
> was
> > not provided as a kwarg. This would enable users to specify the
> edgecolor
> > they want without worrying about something else over-riding it. The only
> > problem seems to be that there would be no shading of these grid lines.
> > Would that still be acceptable to you?
>
> Absolutely acceptable. In fact I think it is preferable not to shade them.
>
> > Thanks for your valuable feedback!
> > Ben Root
>
> Thanks for being responsive to it :)
> regards,
> Gary
>
Good to know. I am currently a little dis-satisfied with the documentation
for plot_surface and I want to expand this significantly. Right now, there
are two different "shadings" that occur depending upon inputs and this
really needs to be spelled out. I will use your input to guide my write-up.
Cheers,
Ben Root
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