DOC: add a basic colorbar examples

phobson · phobson · commit c57cf8a80525 · 2016-09-09T08:39:44.000-07:00
The main thing here is that we have multiple axes and
use the `fig.colorbar` method, specifying which mappables
should be colorbar'd next to which Axes.
diff --git a/examples/api/colorbar_basics.py b/examples/api/colorbar_basics.py
@@ -0,0 +1,28 @@
+import numpy as np
+import matplotlib.pyplot as plt
+
+# setup some generic data
+N = 37
+x, y = np.mgrid[:N, :N]
+Z = (np.cos(x*0.2) + np.sin(y*0.3))
+
+# mask out the negative and positve values, respectively
+Zpos = np.ma.masked_less(Z, 0)
+Zneg = np.ma.masked_greater(Z, 0)
+
+fig, (ax1, ax2) = plt.subplots(figsize=(8, 3), ncols=2)
+
+# plot just the positive data and save the
+# color "mappable" object returned by ax1.imshow
+pos = ax1.imshow(Zpos, cmap='Blues', interpolation='none')
+
+# add the colorbar using the figure's method,
+# telling which mappable we're talking about and
+# which axes object it should be near
+fig.colorbar(pos, ax=ax1)
+
+# repeat everything above for the the negative data
+neg = ax2.imshow(Zneg, cmap='Reds_r', interpolation='none')
+fig.colorbar(neg, ax=ax2)
+
+plt.show()
