I have been looking at this for the past day and in am pretty sure I could replace the instance of polyc by the “cmap if statements” my colour array and I should be able to get close to what I want. However I am new to both python & mpl, and I am not entirely sure in how I would go about testing my hypothesis. Furthermore I am also relatively new to submitting fixes to open-source projects so I have lots of questions about how I would go about suggesting a modification.

 

1.)    can I just modify the file in the C:\python26\Lib\site-packages\mpl-toolkits\mplot3d\axes3d.py file to do my tests?

a.       Also, where are these files usually kept in a linux environment ?

b.      What do I do with the. pyc files with the same name? are they re-complied automatically when I call the function externally?

2.)    Is this capability  already built in with the colour argument ? if so how do I properly call it?

3.)    If I do make a modification should it be as a separate function with the additional variable or should I try to stuff the new capability into the old function

4.)    is there a clean easy to follow tutorial for submitting changes via svn or can I rely on someone else to do the final commit?

 

I have attached the function in question for reference to save others from digging down into their python directories

 

 

Again thanks for taking your time to help me figure this out

 

Mike Alger

 

< Code>

  def plot_surface(self, X, Y, Z, *args, **kwargs):

        '''

        Create a surface plot.

 

        By default it will be colored in shades of a solid color,

        but it also supports color mapping by supplying the *cmap*

        argument.

 

        ==========  ================================================

        Argument    Description

        ==========  ================================================

        *X*, *Y*,   Data values as numpy.arrays

        *Z*

        *rstride*   Array row stride (step size)

        *cstride*   Array column stride (step size)

        *color*     Color of the surface patches

        *cmap*      A colormap for the surface patches.

        ==========  ================================================

        '''

 

        had_data = self.has_data()

 

        rows, cols = Z.shape

        tX, tY, tZ = np.transpose(X), np.transpose(Y), np.transpose(Z)

        rstride = kwargs.pop('rstride', 10)

        cstride = kwargs.pop('cstride', 10)

 

        color = kwargs.pop('color', 'b')

        color = np.array(colorConverter.to_rgba(color))

        cmap = kwargs.get('cmap', None)

 

        polys = []

        normals = []

        avgz = []

        for rs in np.arange(0, rows-1, rstride):

            for cs in np.arange(0, cols-1, cstride):

                ps = []

                corners = []

                for a, ta in [(X, tX), (Y, tY), (Z, tZ)]:

                    ztop = a[rs][cs:min(cols, cs+cstride+1)]

                    zleft = ta[min(cols-1, cs+cstride)][rs:min(rows, rs+rstride+1)]

                    zbase = a[min(rows-1, rs+rstride)][cs:min(cols, cs+cstride+1):]

                    zbase = zbase[::-1]

                    zright = ta[cs][rs:min(rows, rs+rstride+1):]

                    zright = zright[::-1]

                    corners.append([ztop[0], ztop[-1], zbase[0], zbase[-1]])

                    z = np.concatenate((ztop, zleft, zbase, zright))

                    ps.append(z)

 

                # The construction leaves the array with duplicate points, which

                # are removed here.

                ps = zip(*ps)

                lastp = np.array([])

                ps2 = []

                avgzsum = 0.0

                for p in ps:

                    if p != lastp:

                        ps2.append(p)

                        lastp = p

                        avgzsum += p[2]

                polys.append(ps2)

                avgz.append(avgzsum / len(ps2))

 

                v1 = np.array(ps2[0]) - np.array(ps2[1])

                v2 = np.array(ps2[2]) - np.array(ps2[0])

                normals.append(np.cross(v1, v2))

 

        polyc = art3d.Poly3DCollection(polys, *args, **kwargs) ## this is where a modification could be made to allow for a separate colour matrix

        if cmap is not None:

            polyc.set_array(np.array(avgz))

            polyc.set_linewidth(0)

        else:

            colors = self._shade_colors(color, normals)

            polyc.set_facecolors(colors)

 

        self.add_collection(polyc)

        self.auto_scale_xyz(X, Y, Z, had_data)

 

        return polyc

</Code>

 

From: Mike Alger [mailto:mike.alger@ngcaerospace.com]
Sent: November-23-09 3:42 PM
To: matplotlib-users@lists.sourceforge.net
Subject: [Matplotlib-users] Color in 3d plots

 

This may be a dumb question, however I have been scratching my head trying to figure out how to plot a 3 dimensional plot with with a colour map different from the elevation(Z) parameter.

 

An example of this done in Matlab would be

 

[X,Y,Z] = peaks(30);

C=Z'% could be anything other than Z as long as it has the same dimensions

surf(X,Y,Z,C)

 

axis([-3 3 -3 3 -10 5])

 

 

Is this possible with matplotlib '0.99.1'

 

If so how do i go about doing this  is there some sample code?

 

Mike Alger, M.A.Sc

malger@ryerson.ca