Backport PR #9168: Fix pcolormesh and DatetimeIndex error

tacaswell · MeeseeksDev[bot] · commit 788abaf03398 · 2017-09-22T02:10:24.000Z
PR Summary Fixes issue with `DatetimeIndex` and `pcolormesh`: #9167   PR Checklist - [X ] Code is PEP 8 compliant
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -5620,15 +5620,16 @@ def pcolormesh(self, *args, **kwargs):
 
         X, Y, C = self._pcolorargs('pcolormesh', *args, allmatch=allmatch)
         Ny, Nx = X.shape
-
+        X = X.ravel()
+        Y = Y.ravel()
         # unit conversion allows e.g. datetime objects as axis values
         self._process_unit_info(xdata=X, ydata=Y, kwargs=kwargs)
         X = self.convert_xunits(X)
         Y = self.convert_yunits(Y)
 
         # convert to one dimensional arrays
         C = C.ravel()
-        coords = np.column_stack((X.flat, Y.flat)).astype(float, copy=False)
+        coords = np.column_stack((X, Y)).astype(float, copy=False)
 
         collection = mcoll.QuadMesh(Nx - 1, Ny - 1, coords,
                                     antialiased=antialiased, shading=shading,
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -4929,6 +4929,17 @@ def test_broken_barh_empty():
     ax.broken_barh([], (.1, .5))
 
 
+def test_pandas_pcolormesh():
+    pd = pytest.importorskip('pandas')
+
+    time = pd.date_range('2000-01-01', periods=10)
+    depth = np.arange(20)
+    data = np.random.rand(20, 10)
+
+    fig, ax = plt.subplots()
+    ax.pcolormesh(time, depth, data)
+
+
 def test_pandas_indexing_dates():
     pd = pytest.importorskip('pandas')
 
