Mapping fix

lib/iris/plot.py

@@ -365,8 +365,6 @@ def _map_common(draw_method_name, arg_func, mode, cube, data, *args, **kwargs):
         x = numpy.append(x, x[:, 0:1] + 360, axis=1)
         data = numpy.ma.concatenate([data, data[:, 0:1]], axis=1)
 
-
-
     # Get the native crs and map (might be the same cartopy definiton)
     cs = cube.coord_system('CoordSystem')
     cartopy_crs = cs.as_cartopy_crs()  # E.g. Geodetic
@@ -405,7 +403,7 @@ def _map_common(draw_method_name, arg_func, mode, cube, data, *args, **kwargs):
 
     # Set the "from transform" keyword. 
     assert 'transform' not in kwargs, 'Transform keyword is not allowed.' 
-    kwargs['transform'] = cartopy_crs._as_mpl_transform(ax)
+    kwargs['transform'] = cartopy_crs
 
     if arg_func is not None:
         new_args, kwargs = arg_func(x, y, data, *args, **kwargs)
@@ -554,39 +552,37 @@ def map_setup(projection=None, xlim=None, ylim=None, cube=None, mode=None):
     if projection is None:
         projection = cartopy.crs.PlateCarree()
 
+    lim_crs = projection
+
     # Which extents?
     if (xlim is None or ylim is None) and cube is not None:
         mode = mode or iris.coords.BOUND_MODE
         extents = iris.analysis.cartography.xy_range(cube, mode, projection)
         xlim = extents[0]
         ylim = extents[1]
+        lim_crs = cs.as_cartopy_crs() if cs else None
 
     # TODO: Refactor with _map_common()
     # Replace the current axis with a cartopy one
     fig = plt.gcf()
     ax = plt.gca()
     if isinstance(ax, matplotlib.axes.SubplotBase):
-        # xlim = None has special meaning, and must be avoided.
-        if xlim is None:
-            new_ax = fig.add_subplot(ax.get_subplotspec(), projection=projection,
-                                     title=ax.get_title(), xlabel=ax.get_xlabel(),
-                                     ylabel=ax.get_ylabel())
-        else:
-            new_ax = fig.add_subplot(ax.get_subplotspec(), projection=projection,
-                                     xlim=xlim, ylim=ylim,
+        new_ax = fig.add_subplot(ax.get_subplotspec(), projection=projection,
                                      title=ax.get_title(), xlabel=ax.get_xlabel(),
                                      ylabel=ax.get_ylabel())
-
     else:
-        if xlim is None:
-            new_ax = fig.add_axes(projection=projection, #xlim=xlim, ylim=ylim,
-                                  title=ax.get_title(), xlabel=ax.get_xlabel(),
-                                  ylabel=ax.get_ylabel())
-        else:
-            new_ax = fig.add_axes(projection=projection, xlim=xlim, ylim=ylim,
-                                  title=ax.get_title(), xlabel=ax.get_xlabel(),
-                                  ylabel=ax.get_ylabel())
+        new_ax = fig.add_axes(projection=projection,
+                              title=ax.get_title(), xlabel=ax.get_xlabel(),
+                              ylabel=ax.get_ylabel())
+
+    if xlim is not None != ylim is not None:
+        warnings.warn('Both xlim and ylim must currently be set.')
+
+    if xlim is not None:
+        new_ax.set_extent(tuple(xlim) + tuple(ylim), lim_crs)
+
     fig.delaxes(ax)
+    return new_ax
 
 
 def _fill_orography(cube, coords, mode, vert_plot, horiz_plot, style_args):

lib/iris/tests/test_mapping.py

@@ -92,45 +92,36 @@ class TestMappingSubRegion(tests.IrisTest):
     def setUp(self):
         cube_path = tests.get_data_path(('PP', 'aPProt1', 'rotatedMHtimecube.pp'))
         cube = iris.load_strict(cube_path)[0]
-
-        # Until there is better mapping support for rotated-pole, pretend this isn't rotated.
-        # ie. Move the pole from (37.5, 177.5) to (90, 0) and bodge the coordinates.
-#        _pretend_unrotated(cube)
-
-        self.cube = cube
+        # make the data slighly smaller to speed things up...
+        self.cube = cube[::10, ::10]
 
     def test_simple(self):
         # First sub-plot
         plt.subplot(221)
         plt.title('Default')
-
         iplt.contourf(self.cube)
         plt.gca().coastlines()
 
         # Second sub-plot
         plt.subplot(222)
         plt.title('Molleweide')
-
         iplt.map_setup(projection=ccrs.Mollweide(central_longitude=120))
         iplt.contourf(self.cube)
-        plt.gca().set_global()  # TODO: REMOVE THIS ADDITION, PENDING FIX
         plt.gca().coastlines()
 
         # Third sub-plot
         plt.subplot(223)
         plt.title('Native')
-
-        iplt.map_setup(cube=self.cube)
-        iplt.contourf(self.cube)
-        plt.gca().coastlines()
+        ax = iplt.map_setup(cube=self.cube)
+        iplt.contour(self.cube)
+        ax.coastlines()
 
         # Fourth sub-plot
         plt.subplot(224)
-        plt.title('Three/six level')
-
-        contour1 = iplt.contourf(self.cube, 3)
-        contour2 = iplt.contour(self.cube, 6)
-        plt.gca().coastlines()
+        plt.title('PlateCarree')
+        ax = plt.subplot(2, 2, 4, projection=ccrs.PlateCarree())
+        iplt.contourf(self.cube)
+        ax.coastlines()
 
         self.check_graphic()