Fixing color in scatter plots in matplotlib

Setting vmin and vmax should do this.

Here's an example:

import matplotlib.pyplot as plt

xyc = range(20)

plt.subplot(121)
plt.scatter(xyc[:13], xyc[:13], c=xyc[:13], s=35, vmin=0, vmax=20)
plt.colorbar()
plt.xlim(0, 20)
plt.ylim(0, 20)

plt.subplot(122)
plt.scatter(xyc[8:20], xyc[8:20], c=xyc[8:20], s=35, vmin=0, vmax=20)   
plt.colorbar()
plt.xlim(0, 20)
plt.ylim(0, 20)

plt.show()

And the plot this produces: