[Matplotlib-users] Individual custom markers and colorbar

[Hackstein <new...@gm...>]

Hi all,

 

I am trying to get a scatter plot using a colormap. Additionally, I need to
define every marker for every data point individually - each being a
rectangle with fixed height but varying width as a function of the y-value.
X and y being the data coordinates, z being a number to be color coded with
the colormap.

Ideally, I would like to create a list of width and height values for each
data point and tell the scatter plot to use those.

So far I got colormapped data with custom markers (simplified):

 

[code]

 

import numpy as np

import matplotlib.pyplot as plt

from pylab import *

 

x = y = [1,2,3,4,5]

z = [2,4,6,8,10]

 

colors = cm.gnuplot2

 

verts_vec = list(zip([-10.,10.,10.,-10.],[-5.,-5.,5.,5.]))

 

fig = plt.figure(1, figsize=(14.40, 9.00))

ax = fig.add_subplot(1,1,1)

sc = ax.scatter(x, y, c=np.asarray(z), marker=None, edgecolor='None',
verts=verts_vec, cmap=colors, alpha=1.)

plt.colorbar(sc, orientation='horizontal')

plt.savefig('test.png', dpi=200)

plt.close(1)

 

[/code]

 

But I need to define a marker size for each point, and I also need to do
that in axis scale values, not in points.

I imagine giving verts a list of N*2 tuples instead of 2 tuples, N being
len(x), to define N individual markers.

But when doing that I get the error that vertices.ndim==2.

A less elegant way would be to plot every data point in an individual
scatter plot function, using a for-loop iterating over all data points.
Then, however, I see no way to apply a colormap and colorbar.

What is the best way to accomplish that then?

 

Thanks, 

 

-Hackstein