Store original parameters instead of converting units post-hoc (fixes #134)

climix/aggregators.py

@@ -42,7 +42,5 @@ class PointLocalAggregator(Aggregator):
         if proposed_standard_name is not None:
             cube.attributes['proposed_standard_name'] = proposed_standard_name
         for extra_coord in self.index_function.extra_coords:
-            change_units(extra_coord,
-                         self.output_metadata.units, unit_standard_name)
             cube.add_aux_coord(extra_coord)
         return cube

climix/index_functions.py

@@ -67,7 +67,7 @@ class CountOccurrences:
         self.lazy_condition = DASK_OPERATORS[condition]
         self.standard_name = None
         self.units = Unit('days')
-        self.extra_coords = [threshold]
+        self.extra_coords = [threshold.copy()]
 
     def prepare(self, input_cube):
         change_units(self.threshold,
@@ -95,7 +95,7 @@ class FirstOccurrence:
         self.standard_name = None
         self.units = Unit('days')
         self.NO_OCCURRENCE = np.inf
-        self.extra_coords = [threshold]
+        self.extra_coords = [threshold.copy()]
 
     def prepare(self, input_cube):
         change_units(self.threshold,
@@ -143,7 +143,7 @@ class LastOccurrence:
         self.standard_name = None
         self.units = Unit('days')
         self.NO_OCCURRENCE = -np.inf
-        self.extra_coords = [threshold]
+        self.extra_coords = [threshold.copy()]
 
     def prepare(self, input_cube):
         change_units(self.threshold,
@@ -192,7 +192,7 @@ class SpellLength:
         self.reducer = NUMPY_REDUCERS[reducer]
         self.standard_name = None
         self.units = Unit('days')
-        self.extra_coords = [threshold]
+        self.extra_coords = [threshold.copy()]
 
     def prepare(self, input_cube):
         change_units(self.threshold,
@@ -269,7 +269,7 @@ class ThresholdedStatistics:
         self.reducer = NUMPY_REDUCERS[reducer]
         self.lazy_condition = DASK_OPERATORS[condition]
         self.lazy_reducer = DASK_REDUCERS[reducer]
-        self.extra_coords = [threshold]
+        self.extra_coords = [threshold.copy()]
 
     def prepare(self, input_cube):
         change_units(self.threshold,
@@ -300,7 +300,7 @@ class TemperatureSum:
         else:
             self.fun = lambda d, t: np.maximum(t - d, 0)
             self.lazy_fun = lambda d, t: da.maximum(t - d, 0)
-        self.extra_coords = [threshold]
+        self.extra_coords = [threshold.copy()]
 
     def prepare(self, input_cube):
         change_units(self.threshold,