From: Warren Weckesser <warren.weckesser@en...>  20110328 02:23:48

On Sun, Mar 27, 2011 at 8:25 PM, Angus McMorland <amcmorl@...> wrote: > On 27 March 2011 20:47, Warren Weckesser <warren.weckesser@...> > wrote: > > I'm using matplotlib 1.0.1. I have the following simple script to plot a > > surface: > > > >  > > from numpy import linspace, sin, cos, meshgrid > > > > from matplotlib.pyplot import figure, show, xlabel, ylabel > > from matplotlib import cm > > from mpl_toolkits.mplot3d import Axes3D > > > > n = 35 > > x = linspace(5, 5, n) > > y = linspace(0, 10, n) > > X, Y = meshgrid(x, y) > > Z = X*sin(X)*cos(0.25*Y) > > > > fig = figure() > > ax = fig.gca(projection='3d') > > ax.plot_surface(X, Y, Z, rstride=1, cstride=1, cmap=cm.copper) > > xlabel('x') > > ylabel('y') > > show() > >  > > > > It works finemany thanks to all the folks working on the 3D plots! > > > > But notice that Axes3D is imported from matplotlib.mplot3d, but never > > explicitly used. If I comment out that import, however, I get the > following > > traceback: > >  > > Traceback (most recent call last): > > File "surf_demo.py", line 15, in <module> > > ax = fig.gca(projection='3d') > > File > > > "/Library/Frameworks/Python.framework/Versions/7.0/lib/python2.7/sitepackages/matplotlib/figure.py", > > line 965, in gca > > return self.add_subplot(111, **kwargs) > > File > > > "/Library/Frameworks/Python.framework/Versions/7.0/lib/python2.7/sitepackages/matplotlib/figure.py", > > line 675, in add_subplot > > projection_class = get_projection_class(projection) > > File > > > "/Library/Frameworks/Python.framework/Versions/7.0/lib/python2.7/sitepackages/matplotlib/projections/__init__.py", > > line 61, in get_projection_class > > raise ValueError("Unknown projection '%s'" % projection) > > ValueError: Unknown projection '3d' > >  > > > > Is this expected? > > Yes, the last lines of axes3d.py, which get called when Axes3D is imported, > are: > > import matplotlib.projections as proj > proj.projection_registry.register(Axes3D) > > which is what lets matplotlib know about the '3d' projection. Just > importing the Axes3D module therefore performs the necessary > registration of the projection to be able to use it in subsequent > code. Code analysis tools like rope don't know about this behind the > scenes stuff though, so it looks like a redundant import to them. > OK, thanks. Warren > > Angus. >  > AJC McMorland > Postdoctoral research fellow > Neurobiology, University of Pittsburgh > 