Change default color map (Fix matplotlib#875)

doc/users/whats_new/style_changes.rst

@@ -24,6 +24,9 @@ These changes include:
   has been changed.  It is based on the Dark2 qualitative color
   palette from `colorbrewer <http://colorbrewer2.org/>`__.
 
+- The default color map used for images and pcolor meshes, etc., has
+  changed from ``jet`` to ``viridis``.
+
 - For markers, scatter plots, bar charts and pie charts, there is no
   longer a black outline around filled markers by default.
 
@@ -57,5 +60,6 @@ These changes include:
 
 - By default, caps on the ends of errorbars are not present.
 
-- The ''Blues'' colormap has been adjusted to be perceptually uniform.  The old
-  ``blues`` colormap is available under the name ``legacy_Blues``.
+- The ''Blues'' colormap has been adjusted to be perceptually uniform.
+  The old ``blues`` colormap is available under the name
+  ``legacy_Blues``.

lib/matplotlib/rcsetup.py

@@ -907,7 +907,7 @@ def validate_cycler(s):
 
     'image.aspect':        ['equal', validate_aspect],  # equal, auto, a number
     'image.interpolation': ['nearest', six.text_type],
-    'image.cmap':          ['jet', six.text_type],        # one of gray, jet, etc
+    'image.cmap':          ['viridis', six.text_type],        # one of gray, jet, etc
     'image.lut':           [256, validate_int],  # lookup table
     'image.origin':        ['upper', six.text_type],  # lookup table
     'image.resample':      [False, validate_bool],

matplotlibrc.template

@@ -428,7 +428,7 @@ backend      : %(backend)s
 ### IMAGES
 #image.aspect : equal             # equal | auto | a number
 #image.interpolation  : nearest   # see help(imshow) for options
-#image.cmap   : jet               # gray | jet etc...
+#image.cmap   : viridis           # A colormap name, gray etc...
 #image.lut    : 256               # the size of the colormap lookup table
 #image.origin : upper             # lower | upper
 #image.resample  : False