Fixing an issue where line and scatter plots weren't respecting the y…

…axis keyword argument. Added a test and reference plot.

cis/plotting/genericplot.py

@@ -12,7 +12,7 @@
 @six.add_metaclass(ABCMeta)
 class APlot(object):
 
-    def __init__(self, packed_data, xaxis, yaxis, color=None,
+    def __init__(self, packed_data, xaxis, yaxis=None, color=None,
                  edgecolor=None, itemstyle=None, itemwidth=None, label=None, *mplargs, **mplkwargs):
         """
         Abstract base class for all CIS plot types. Includes some common kwargs.

cis/plotting/plot.py

@@ -334,6 +334,7 @@ def basic_plot(data, how=None, ax=None, xaxis=None, yaxis=None, projection=None,
     from cis.data_io.common_data import CommonData
     from cis.data_io.gridded_data import GriddedData
     from cis.utils import squeeze
+    from cis.plotting.genericplot import GenericPlot
 
     # Remove any extra gridded data dimensions
     if isinstance(data, GriddedData):
@@ -346,23 +347,32 @@ def basic_plot(data, how=None, ax=None, xaxis=None, yaxis=None, projection=None,
                                  "histogram2d or use a Coord (or None) for the xaxis argument.")
         else:
             how = 'comparativescatter'
+        xaxis_coord = xaxis
     else:
-        xaxis = get_axis(data, 'X', xaxis)
+        xaxis_coord = get_axis(data, 'X', xaxis)
 
-    yaxis = get_axis(data, 'Y', yaxis)
+    yaxis_coord = get_axis(data, 'Y', yaxis)
 
-    how = how or data._get_default_plot_type(xaxis.standard_name == 'longitude'
-                                             and yaxis.standard_name == 'latitude')
-
-    # Set a nice default label
-    label = get_label(data) if label is None else label
+    how = how or data._get_default_plot_type(xaxis_coord.standard_name == 'longitude'
+                                             and yaxis_coord.standard_name == 'latitude')
 
     try:
-        plot = plot_types[how](data, xaxis=xaxis, yaxis=yaxis, label=label,
-                               *args, **kwargs)
+        plt_type = plot_types[how]
     except KeyError:
         raise ValueError("Invalid plot type, must be one of: {}".format(plot_types.keys()))
 
+    if issubclass(plt_type, GenericPlot) and yaxis is not None:
+        # If we have a line or scatter plot and the user has specified a y-axis, then this should be the data
+        data = yaxis_coord
+    else:
+        # Otherwise, it's just another kwarg
+        kwargs['yaxis'] = yaxis_coord
+
+    # Set a nice default label
+    label = get_label(data) if label is None else label
+
+    plot = plot_types[how](data, xaxis=xaxis_coord, label=label, *args, **kwargs)
+
     subplot_kwargs = {}
     if plot.is_map():
         if projection is None:
@@ -381,10 +391,10 @@ def basic_plot(data, how=None, ax=None, xaxis=None, yaxis=None, projection=None,
     plot(ax)
 
     # Any post-processing
-    if xaxis.standard_name == 'time' and how not in ['comparativescatter', 'histogram2d', 'histogram']:
+    if xaxis_coord.standard_name == 'time' and how not in ['comparativescatter', 'histogram2d', 'histogram']:
         set_x_axis_as_time(ax)
 
-    if yaxis.standard_name == 'air_pressure':
+    if yaxis_coord.standard_name == 'air_pressure':
         ax.invert_yaxis()
 
     return plot, ax

cis/test/plot_tests/test_plotting.py

@@ -982,3 +982,10 @@ def test_mercator_projection(self):
         ax.bluemarble()
 
         self.check_graphic()
+
+    def test_can_specify_yaxis_altitude(self):
+        from cis import read_data
+        d = read_data(valid_GASSP_aeroplane_filename, valid_GASSP_aeroplane_variable)
+        d.plot(yaxis='altitude')
+
+        self.check_graphic()

doc/whats_new_1.5.rst

@@ -34,3 +34,4 @@ Bugs fixed
 CIS 1.5.1 fixes
 ===============
  * Minor fix in interpreting units when reading some NetCDF data in Python 2
+ * Fixed an issue where line and scatter plots weren't respecting the yaxis keyword