Creating a function that takes two vectors used to make a scatter plot and converts them into the three arrays need for a contour plot.

ScatterToContour.py

import numpy as np
import matplotlib.pyplot as plt

def ScatterToContour(x,y, bins=[10,10]):
	'''
	x is the x location of the points
	y is the y location of the points
	len(x) needs to equal len(y)
	bins determins the refinement of the histogram and line edges.
	All contour plot perameters (levels, ect.) are defined outside 
		but bins my have a minor effect on these
	'''
	xlist = np.linspace(min(x), max(x), bins[0])
	ylist = np.linspace(min(y), max(y), bins[1])
	X, Y = np.meshgrid(xlist, ylist)
	H, xedges, yedges = np.histogram2d(x,y,bins)
	H = np.rot90(H) #no idea why, but it works with asymetric plots.
	H = np.flipud(H)
	return X, Y, H

x = np.append( np.random.randn(9000), np.random.normal(4,2,1000)) #make the plots asymetirc aobut the center. 
x = np.append( x, np.random.normal(14,1,5000)) #add an extra area so it has two peaks
# x = np.random.randn(10100) #more uniform
y = np.random.normal(0, 2, 15000)

plt.figure(1)
plt.scatter(x,y)
plt.savefig('scatter.pdf')
plt.show()

plt.figure(2)
xplot, yplot, z = ScatterToContour(x,y)
plt.pcolormesh(xplot,yplot,z)
plt.contour(xplot,yplot,z)
plt.savefig('contour.pdf')
plt.show()

##############################
# Created by Ben Rose
# on 2014-04-17
# brose3@nd.edu
# shared under the MIT license
##############################