Fix for JASCIS-199. Aggregation now correctly uses the bounds supplie…

…d by the user even when collapsing to length one coordinates.

cis/aggregation/aggregator.py

@@ -156,18 +156,23 @@ def _make_partially_collapsed_coord(self, coord, grid, guessed_axis):
         new_coordinate_grid = aggregation_grid_array(grid_start, grid_end, grid_delta, grid.is_time, coord)
         new_coord = DimCoord(new_coordinate_grid, var_name=coord.name(), standard_name=coord.standard_name,
                              units=coord.units)
-        new_coord.guess_bounds()
+        if len(new_coord.points) == 1:
+            new_coord.bounds = [[grid_start, grid_end]]
+        else:
+            new_coord.guess_bounds()
         return new_coord
 
     def _add_max_min_bounds_for_collapsed_coords(self, aggregated_cube, source_cube):
         """
-        Add bounds onto all coordinates which have been full collapsed. These bounds will
-        be the maximum and minimum values of those coordinates
+        Add bounds onto all coordinates which have been full collapsed, and for which no explicit bounds have been
+        supplied (iris will have guessed these to be +/- inf). The new bounds will be the maximum and minimum values of
+        those coordinates
         :param aggregated_cube: The aggregated cube to give new bounds
         :param source_cube: The source cube which the aggregation was made from.
         """
+        from numpy import isinf, all
         for coord in aggregated_cube.coords():
-            if len(coord.points) == 1:
+            if len(coord.points) == 1 and all(isinf(coord.bounds)):
                 source_coord = source_cube.coord(coord.name())
                 coord_start, coord_end, coord_centre = self._get_coord_start_end_centre(source_coord)
                 coord.bounds = numpy.array([[coord_start, coord_end]])

cis/test/unit/aggregation/test_aggregation.py

@@ -449,6 +449,21 @@ def test_collapsed_coords_get_max_min_bounds(self):
         lon = output.coord('longitude')
         assert_arrays_equal(lon.bounds, [[-5, 5]])
 
+    def test_aggregating_coord_to_length_one_with_explicit_bounds_gets_output_as_length_one(self):
+        data = make_regular_2d_ungridded_data()
+        grid = {'x': AggregationGrid(-180, 180, 360, False), 'y': AggregationGrid(-90, 90, 10, False), }
+        agg = Aggregator(data, grid)
+        output = agg.aggregate_ungridded(self.kernel)
+        lon = output.coord('longitude')
+        assert_that(lon.points, is_([0]))
+
+    def test_aggregating_to_length_one_with_explicit_bounds_get_correct_bounds(self):
+        data = make_regular_2d_ungridded_data()
+        grid = {'x': AggregationGrid(-180, 180, 360, False), 'y': AggregationGrid(-90, 90, 10, False), }
+        agg = Aggregator(data, grid)
+        output = agg.aggregate_ungridded(self.kernel)
+        lon = output.coord('longitude')
+        assert_arrays_equal(lon.bounds, [[-180, 180]])
 
 class TestUngriddedListAggregation(TestCase):