from matplotlib.pyplot import figure, show
from numpy import arange, pi, cos, sin, pi
from numpy.random import rand

# unit area ellipse
rx, ry = 3., 1.
area = rx * ry * pi
theta = arange(0, 2*pi+0.01, 0.1)
verts = zip(rx/area*cos(theta), ry/area*sin(theta))

x,y,s,c = rand(4, 30)
s*= 10**2.

fig = figure()
ax = fig.add_subplot(111)
ax.scatter(x,y,s,c,marker=None,verts =verts)

show()