Fixing color in scatter plots in matplotlib

Question

I want to fix the color range on multiple scatter plots and add in a colorbar to each plot (which will be the same in each figure). Essentially, I'm fixing all aspects of the axes and colorspace etc. so that the plots are directly comparable by eye.

For the life of me, I can't seem to figure out all the various ways of fixing the color-range. I've tried vmin, vmax, but it doesn't seem to do anything, I've also tried clim(x,y) and that doesn't seem to work either.

This must come up here and there, I can't be the only one that wants to compare various subsets of data amongst plots... so, how do you fix the colors so that each data keeps it's color between plots and doesn't get remapped to a different color due to the change in max/min of the subset -v- the whole set?

I greatly appreciate all your thoughts!!!

A mountain-dew and fiery-hot cheetos to all! -Allen

Answer 1

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: