is there any more information you'd like to help me with
> constructing a legend for this scatter?
> i think i am misusing the scatter graph here... letting
> scatter assign colours from a continous selection rather
> than specifying a color.
Yes, you probably want to assign specific colors in multiple calls to
scatter. Scatter returns a
matplotlib.collections.RegularPolyCollection, which legend is not
equiped to deal with. To hack around this, you can create a proxy
patch to pass to legend, which has the colors you want to use for the
legend
from matplotlib.patches import Rectangle
from pylab import *
N=20
props = dict( alpha=0.75, faceted=False )
x, y= rand(2,N)
s=array(([400]+[30]*(N/2-1))*2)
reds = scatter(x, y, c='red', s=s, **props)
x, y= rand(2,N)
s=array(([400]+[30]*(N/2-1))*2)
blues = scatter(x, y, c='blue', s=s, **props)
redp = Rectangle( (0,0), 1,1, facecolor='red')
bluep = Rectangle( (0,0), 1,1, facecolor='blue')
legend( (redp, bluep), ('reds', 'blues') )
grid(True)
show()