import numpy as np
import matplotlib.pyplot as plt

data = np.genfromtxt('my_db.csv', delimiter=',',usecols=(1,2,3),names=['z','y','x'])

x = data['x']
y = data['y']

hist,xedges,yedges = np.histogram2d(x,y,bins=40)
extent = [xedges[0], xedges[-1], yedges[0], yedges[-1] ]
plt.imshow(hist.T,extent=extent,interpolation='nearest',origin='lower')
plt.colorbar()
plt.show()