matplotlib Plot multiple scatter plots, each colored by different thrid variable

Question

I'm trying to plot multiple pairs of data on a single scatter plot, each colored by a different third variable array. The coloring seems to work for the first plot, then fails for the second and third.

Any help would be appreciated

import matplotlib.pyplot as plt

jet=plt.get_cmap('jet')

x = [1,2,3,4]
y = [1,2,3,4]
z = [1,1,1,1]

a = [2,3,4,5]
b = [1,2,3,4]
c = [2,2,2,2]

d = [3,4,5,6]
e = [1,2,3,4]
f = [3,3,3,3]

plt.scatter(x, y, s=100, c=z, cmap=jet)
plt.scatter(a, b, s=100, c=c, cmap=jet)
plt.scatter(d, e, s=100, c=f, cmap=jet)

plt.clim(0,5)
plt.colorbar()
plt.show()

I have seen that. Those examples are for a single scatter plot. My coloring fails for subsequent scatter plots. — emunson5
– emunson5, Commented Mar 23, 2015 at 0:00
why do you want to color using the third variable since all values in the color lists are the same? — Julien Spronck
– Julien Spronck, Commented Mar 23, 2015 at 0:00
Good point, I just used this as a mockup of my real data where I need the arrays separate to control the symbols and create a legend (the data is from analyses on the different samples) — emunson5
– emunson5, Commented Mar 23, 2015 at 0:03

Julien Spronck · Accepted Answer · 2015-03-23 00:07:14Z

2

I have removed the plt.clim(0,5) line and added minimal and maximal values for all plots and that seems to work.

import matplotlib.pyplot as plt

jet=plt.get_cmap('jet')

x = [1,2,3,4]
y = [1,2,3,4]
z = [1,1,1,1]

a = [2,3,4,5]
b = [1,2,3,4]
c = [2,2,2,2]

d = [3,4,5,6]
e = [1,2,3,4]
f = [3,3,3,3]

plt.scatter(x, y, s=100, c=z, vmin=1, vmax=5, cmap=jet)
plt.scatter(a, b, s=100, c=c, vmin=1, vmax=5, cmap=jet)
plt.scatter(d, e, s=100, c=f, vmin=1, vmax=5, cmap=jet)

plt.colorbar()
plt.show()

answered Mar 23, 2015 at 0:07

Julien Spronck

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8one6 · Accepted Answer · 2015-03-23 00:09:57Z

2

The problem is that your colormap is being renormalized for each of your plot commands. Also. As a matter of style, jet is basically never the right colormap to use. So try this:

import matplotlib.pyplot as plt

jet=plt.get_cmap('coolwarm')

x = [1,2,3,4]
y = [1,2,3,4]
z = [1,1,1,1]

a = [2,3,4,5]
b = [1,2,3,4]
c = [2,2,2,2]

d = [3,4,5,6]
e = [1,2,3,4]
f = [3,3,3,3]

plt.scatter(x, y, s=100, c=z, cmap=jet, vmin=0, vmax=4)
plt.scatter(a, b, s=100, c=c, cmap=jet, vmin=0, vmax=4)
plt.scatter(d, e, s=100, c=f, cmap=jet, vmin=0, vmax=4)

plt.clim(0,5)
plt.colorbar()
plt.show()

Makes a nice plot: enter image description here

answered Mar 23, 2015 at 0:09

8one6

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