Fix for JASCIS-342. gridded->gridded collocation now won't exrapolate…

… by default, and the collocation argument will be passed through properly.

cis/collocation/col.py

@@ -29,10 +29,10 @@ def get_collocator_instances_for_method(self, method_name, kernel_name, collocat
         :param data_gridded: Is the collocation data gridded?
         :return: Collocator, Constrain and Kernel instances
         """
-        import cis.collocation.col_implementations as ci
+
         col_cls, constraint_cls, kernel_cls = self._get_collocator_classes_for_method(method_name, kernel_name,
                                                                                       sample_gridded, data_gridded)
-        collocator_params, constraint_params = self._get_collocator_params(collocator_params)
+        collocator_params, constraint_params = self._get_collocator_params(collocator_params, col_cls)
         col = self._instantiate_with_params(col_cls, collocator_params)
         con = self._instantiate_with_params(constraint_cls, constraint_params)
         kernel = self._instantiate_with_params(kernel_cls, kernel_params)
@@ -104,17 +104,23 @@ def _get_collocator_classes_for_method(self, method_name, kernel_name, sample_gr
                     'A kernel cannot be specified for collocator "{}"'.format(method_name))
         return option
 
-    def _get_collocator_params(self, params):
+    def _get_collocator_params(self, params, col_cls):
         """
         Separates the parameters understood by the collocator from those for the constraint.
         :param params: combined collocator/constraint parameters
+        :param col_cls: The collocator class to check for parameters against
         :return: tuple containing (dict of collocator parameters, dict of constraint parameters)
         """
-        col_param_names = ['fill_value', 'var_name', 'var_long_name', 'var_units', 'missing_data_for_missing_sample']
+        import inspect
+        # Python 2/3 compatibility
+        if hasattr(inspect, 'signature'):
+            args = inspect.signature(col_cls.__init__).parameters
+        else:
+            args = inspect.getargspec(col_cls.__init__).args
         col_params = {}
         con_params = {}
         for key, value in params.items():
-            if key in col_param_names:
+            if key in args:
                 col_params[key] = value
             else:
                 con_params[key] = value

cis/collocation/col_implementations.py

@@ -572,6 +572,12 @@ class nn_t(nn_time):
 
 class GriddedCollocator(Collocator):
 
+    def __init__(self, fill_value=np.nan, var_name='', var_long_name='', var_units='',
+                 missing_data_for_missing_sample=False, extrapolate=False):
+        super(GriddedCollocator, self).__init__(fill_value, var_name, var_long_name, var_units,
+                                                         missing_data_for_missing_sample)
+        self.extrapolate = 'extrapolate' if extrapolate else 'mask'
+
     @staticmethod
     def _check_for_valid_kernel(kernel):
         from cis.exceptions import ClassNotFoundError
@@ -667,7 +673,7 @@ def collocate(self, points, data, constraint, kernel):
 
         output_cube = self._iris_interpolate(coord_names_and_sizes_for_output_grid,
                                              coord_names_and_sizes_for_sample_grid, data,
-                                             kernel, output_mask, points)
+                                             kernel, output_mask, points, self.extrapolate)
 
         if not isinstance(output_cube, list):
             return GriddedDataList([output_cube])
@@ -700,7 +706,7 @@ def _make_output_mask(coord_names_and_sizes_for_sample_grid, output_shape, point
 
     @staticmethod
     def _iris_interpolate(coord_names_and_sizes_for_output_grid, coord_names_and_sizes_for_sample_grid, data, kernel,
-                          output_mask, points):
+                          output_mask, points, extrapolate):
         """ Collocates using iris.analysis.interpolate
         """
         coordinate_point_pairs = []
@@ -712,7 +718,8 @@ def _iris_interpolate(coord_names_and_sizes_for_output_grid, coord_names_and_siz
 
         # The result here will be a cube with the correct dimensions for the output, so interpolated over all points
         # in coord_names_and_sizes_for_output_grid.
-        output_cube = make_from_cube(data.interpolate(coordinate_point_pairs, kernel.interpolater()))
+        output_cube = make_from_cube(data.interpolate(coordinate_point_pairs,
+                                                      kernel.interpolater(extrapolation_mode=extrapolate)))
 
         # Iris outputs interpolated cubes with the dimensions in the order of the data grid, not the sample grid,
         # so we need to rearrange the order of the dimensions.

doc/whats_new_1.4.rst

@@ -10,6 +10,9 @@ CIS 1.4 features
 ================
 
  * CIS now includes full support for Python 3, as well as Python 2.7
+ * New verbose and quiet flags allow for control over how much CIS commands output to the screen. The default verbosity
+   has also changed so that by default only warnings and errors will be output to the screen. The full debug output
+   remains for the cis.log file.
  * Significant optimizations have been made in gridded -> ungridded collocation which should now be considerably faster.
    Also, when collocating multiple gridded source datasets the interpolation indices are now cached internally leading
    to further time savings.
@@ -26,9 +29,9 @@ CIS 1.4 features
    ``valid_min`` or ``valid_max`` attributes is also masked appropriately.
  * CloudSat ``missing`` and ``missop`` attributes are now read and combined to mask out values which don't conform to the
    inequality defined.
- * New verbose and quiet flags allow for control over how much CIS commands output to the screen. The default verbosity
-   has also changed so that by default only warnings and errors will be output to the screen. The full debug output
-   remains for the cis.log file.
+ * [JASCIS-342] The extrapolation modes are now consistent across both gridded->gridded and gridded->ungridded collocation
+   modes. The default is no extrapolation (gridded->gridded would previously extrapolate). This can still be overridden
+   by the user.
 
 Bugs fixed
 ==========