On Wed, Oct 13, 2010 at 5:46 PM, Pedro M. Ferreira
<pmffferre...@gmail.com>wrote:
> Hi All,
>
> I have been trying to make a 3D scatter plot using mplot3d and I would
> like the markers to have their colour according to the Z value.
> >From what I understood in the tutorial and API I have to use the cmap
> and norm kwargs, but all my attempts failed.
>
> I am trying to do it like this:
> ax.scatter(x,y,z,s=10,marker='o',c=????,cmap=????,norm=????)
>
> However I am not sure what to pass to c, cmap and norm.
>
> Any help ?
> Thanks.
>
> Cheers,
> Pedro
>
>
It has been a while since I played around with this, and I am working
completely off my memory right now, but here goes...
If I remember correctly, the 'c' values can be an array that is parallel to
the x, y, z arrays and specifies the color in one of two ways. First, the
array could have a list of color specs (e.g., 'k', 'r', 'b'). Second, the
array could contain values that would be passed to the colormap to retrieve
the colorspec according to where the value lies on the scale of 0 to 1.
If you want to use just simple colors, go ahead and just make a list of
characters like so:
['k', 'r', 'g', 'g', 'b', 'k']
based on whatever the values are in z (I recommend using numpy's where()
function for this.
I am not 100% sure if you need the following or if mpl will just autoscale
for you. So you might want to first just try out using the 'c' keyword.
If you want to use the colormap, then the values passed into c either has to
be the normalized values of z
c = (z - z.min()) / (z.max()-z.min())
or you can use one of the Normalize classes in matplotlib.color (assuming
you have imported matplotlib.pyplot as plt):
norm = plt.Normalize(z.min(), z.max())
or whatever minimum and/or maximum values you wish.
I believe you can use the default colormap by not specifying anything at all
for cmap, but I could be wrong here. You can also specify any colormap by
their name like 'spring', 'jet', 'bone' and so on.
I hope that helps.
Ben Root
------------------------------------------------------------------------------
Beautiful is writing same markup. Internet Explorer 9 supports
standards for HTML5, CSS3, SVG 1.1, ECMAScript5, and DOM L2 & L3.
Spend less time writing and rewriting code and more time creating great
experiences on the web. Be a part of the beta today.
http://p.sf.net/sfu/beautyoftheweb
_______________________________________________
Matplotlib-users mailing list
Matplotlib-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/matplotlib-users
