DOC: reword non-monotinc cell center warning

jklymak · jklymak · commit 48cc1706a0aa · 2020-09-14T13:36:45.000-07:00
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -5578,13 +5578,14 @@ def _interp_grid(X):
                         dX = np.diff(X, axis=1)/2.
                         if not (np.all(dX >= 0) or np.all(dX <= 0)):
                             cbook._warn_external(
-                                f"The input coordinates to {funcname} are "
-                                "not all either increasing or decreasing, "
-                                "the automatically computed edges can "
-                                "produce misleading results in this case. "
-                                "It is recommended to supply the "
-                                f"quadrilateral edges to {funcname}"
-                                f" yourself. See help({funcname}).")
+                                f"Mesh cell edges are being inferred from "
+                                f"mesh cell centers, but the input "
+                                f"coordinates to {funcname} are not "
+                                "monotonically increasing or decreasing. The "
+                                "inferred cell edges can produce misleading "
+                                "results in this case. If so, it is possible "
+                                "to supply the quadrilateral edges to "
+                                f"{funcname} yourself.")
                         X = np.hstack((X[:, [0]] - dX[:, [0]],
                                        X[:, :-1] + dX,
                                        X[:, [-1]] + dX[:, [-1]]))
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -1180,7 +1180,7 @@ def test_pcolorargs():
     y = [-10, 10]
     X, Y = np.meshgrid(x, y)
     Z = np.zeros(X.shape)
-    with pytest.warns(UserWarning, match="The input coordinates"):
+    with pytest.warns(UserWarning, match="Mesh cell edges are being inferred"):
         ax.pcolormesh(X, Y, Z, shading='auto')
 
 
