Allow 1D plots to have the coordinate on the y-axis.

CHANGES

@@ -1,3 +1,17 @@
+Release 1.5 (unreleased)
+========================
+
+
+Features added
+--------------
+* A new transpose keyword argument for `iris.plot.plot` and `iris.quickplot.plot`
+  allows the coordinate of a 1d plot to be presented on the y-axis with the data
+  values on the x-axis.
+
+
+----------------------------
+
+
 Release 1.4 (unreleased)
 ========================
 

docs/iris/src/whatsnew/1.5.rst

@@ -0,0 +1,30 @@
+What's new in Iris 1.5
+**********************
+
+:Release: 1.5.0
+:Date: unreleased
+
+This document explains the new/changed features of Iris in version 1.5.
+
+Iris 1.5 features
+=================
+
+A summary of the main features added with version 1.5:
+
+* A new transpose keyword argument for :func:`iris.plot.plot` and
+  :func:`iris.quickplot.plot` allows the coordinate of a 1d plot to be
+  presented on the y-axis with the data values on the x-axis.
+
+Bugs fixed
+----------
+* N/A
+
+Incompatible changes
+--------------------
+* N/A
+
+Deprecations
+------------
+* N/A
+
+

lib/iris/plot.py

@@ -328,6 +328,11 @@ def _draw_1d_from_points(draw_method_name, arg_func, cube, *args, **kwargs):
     else:
         u = np.arange(data.shape[0])
 
+    # get & remove the transpose entry from kwargs
+    transpose = kwargs.pop('transpose', False)
+    if transpose:
+        u, data = data, u
+
     draw_method = getattr(plt, draw_method_name)
     if arg_func is not None:
         args, kwargs = arg_func(u, data, *args, **kwargs)
@@ -718,6 +723,12 @@ def plot(cube, *args, **kwargs):
         element is the horizontal axis of the plot and the second element is
         the vertical axis of the plot.
 
+    * transpose: True or False
+        If False the plot will have the coordinate on the x-axis and the data
+        values on the y-axis. If True the plot axes will be transposed with the
+        coordinate on the y-axis and the data values on the x-axis. This is
+        suitable for vertical profile type plots. Defaults to False.
+
     See :func:`matplotlib.pyplot.plot` for details of other valid keyword
     arguments.
 

lib/iris/quickplot.py

@@ -52,7 +52,7 @@ def _title(cube_or_coord, with_units):
     return title
 
 
-def _label(cube, mode, result=None, ndims=2, coords=None):
+def _label(cube, mode, result=None, ndims=2, coords=None, transpose1d=False):
     """Puts labels on the current plot using the given cube."""
 
     plt.title(_title(cube, with_units=False))
@@ -82,8 +82,14 @@ def _label(cube, mode, result=None, ndims=2, coords=None):
             plt.ylabel(_title(plot_defn.coords[0], with_units=True))
             plt.xlabel(_title(plot_defn.coords[1], with_units=True))
     elif ndims == 1:
-        plt.xlabel(_title(plot_defn.coords[0], with_units=True))
-        plt.ylabel(_title(cube, with_units=True))
+        cube_title = _title(cube, with_units=True)
+        coord_title = _title(plot_defn.coords[0], with_units=True)
+        if transpose1d:
+            plt.xlabel(cube_title)
+            plt.ylabel(coord_title)
+        else:
+            plt.xlabel(coord_title)
+            plt.ylabel(cube_title)
     else:
         raise ValueError('Unexpected number of dimensions (%s) given to _label.' % ndims)
 
@@ -92,8 +98,9 @@ def _label_with_bounds(cube, result=None, ndims=2, coords=None):
     _label(cube, iris.coords.BOUND_MODE, result, ndims, coords)
 
 
-def _label_with_points(cube, result=None, ndims=2, coords=None):
-    _label(cube, iris.coords.POINT_MODE, result, ndims, coords)
+def _label_with_points(cube, result=None, ndims=2, coords=None,
+                       transpose1d=False):
+    _label(cube, iris.coords.POINT_MODE, result, ndims, coords, transpose1d)
 
 
 def contour(cube, *args, **kwargs):
@@ -200,6 +207,7 @@ def plot(cube, *args, **kwargs):
 
     """
     coords = kwargs.get('coords')
+    transpose = kwargs.get('transpose', False)
     result = iplt.plot(cube, *args, **kwargs)
-    _label_with_points(cube, ndims=1, coords=coords)
+    _label_with_points(cube, ndims=1, coords=coords, transpose1d=transpose)
     return result

lib/iris/tests/test_plot.py

@@ -139,6 +139,24 @@ def test_orography(self):
             self.check_graphic()
 
 
+@iris.tests.skip_data
+class Test1dPlotTranspose(tests.GraphicsTest):
+
+    def setUp(self):
+        path = tests.get_data_path(('NetCDF', 'ORCA2', 'votemper.nc'))
+        self.cube = iris.load_cube(path)[0, :, 60, 80]
+
+    def test_transpose_true(self):
+        # put the coordinate on the y-axis
+        qplt.plot(self.cube, transpose=True)
+        self.check_graphic()
+
+    def test_transpose_false(self):
+        # put the coordinate on the x-axis (normal behaviour)
+        qplt.plot(self.cube, transpose=False)
+        self.check_graphic()
+
+
 # Caches _load_4d_testcube so subsequent calls are faster
 def cache(fn, cache={}):
     def inner(*args, **kwargs):