add changelog entry, rename flag from 'kind' to 'axis_type'

CHANGES.rst

@@ -26,8 +26,10 @@ New Features
 
 - Add a ``StokesFrame`` which converts from 'I', 'Q', 'U', 'V' to 0-3. [#133]
 
-- Support serialising the base ``CoordinateFrame`` class to asdf, by making
-  a specific tag and schema for ``Frame2D`` [#150]
+- Support serializing the base ``CoordinateFrame`` class to asdf, by making
+  a specific tag and schema for ``Frame2D``. [#150]
+
+- Generalized the footrpint calculation to all output axes. [#167]
 
 
 API Changes
@@ -36,6 +38,8 @@ API Changes
 - The argument ``output="numerical_plus"`` was replaced by a bool
   argument ``with_units``. [#156]
 
+- Added a new flag ``axis_type`` to the footprint method. It controls what
+  type of footprint to calculate. [#167]
 
 Bug Fixes
 ^^^^^^^^^

gwcs/tests/test_wcs.py

@@ -317,12 +317,12 @@ def test_footprint():
                                           [15, 0, 12],
                                           [15, 2, 2],
                                           [15, 2, 12]]))
-    assert_equal(w.footprint(kind='spatial'), np.array([[ 11.,   0.],
-                                                        [ 11.,   2.],
-                                                        [ 15.,   2.],
-                                                        [ 15.,   0.]]))
+    assert_equal(w.footprint(axis_type='spatial'), np.array([[ 11.,   0.],
+                                                             [ 11.,   2.],
+                                                             [ 15.,   2.],
+                                                             [ 15.,   0.]]))
 
-    assert_equal(w.footprint(kind='spectral'), np.array([2, 12]))
+    assert_equal(w.footprint(axis_type='spectral'), np.array([2, 12]))
 
 
 class TestImaging(object):

gwcs/wcs.py

@@ -519,7 +519,7 @@ def __repr__(self):
             self.output_frame, self.input_frame, self.forward_transform)
         return fmt
 
-    def footprint(self, bounding_box=None, center=False, kind="all"):
+    def footprint(self, bounding_box=None, center=False, axis_type="all"):
         """
         Return the footprint in world coordinates.
 
@@ -529,7 +529,7 @@ def footprint(self, bounding_box=None, center=False, kind="all"):
             `prop: bounding_box`
         center : bool
             If `True` use the center of the pixel, otherwise use the corner.
-        kind : str
+        axis_type : str
             A supported ``output_frame.axes_type`` or "all" (default).
             One of ['spatial', 'spectral', 'temporal'] or a custom type.
 
@@ -538,7 +538,7 @@ def footprint(self, bounding_box=None, center=False, kind="all"):
         coord : ndarray
             Array of coordinates in the output_frame mapping
             corners to the output frame. For spatial coordinates the order
-            is clockwise.
+            is clockwise, starting from the bottom left corner.
 
         """
         def _order_clockwise(v):
@@ -564,17 +564,17 @@ def _order_clockwise(v):
 
         result = np.asarray(self.__call__(*vertices, **{'with_bounding_box': False}))
 
-        kind = kind.lower()
-        if kind == 'spatial' and all_spatial:
+        axis_type = axis_type.lower()
+        if axis_type == 'spatial' and all_spatial:
             return result.T
 
-        if kind != "all":
-            axtyp_ind = np.array([t.lower() for t in self.output_frame.axes_type]) == kind
+        if axis_type != "all":
+            axtyp_ind = np.array([t.lower() for t in self.output_frame.axes_type]) == axis_type
             if not axtyp_ind.any():
-                raise ValueError('This WCS does not have axis of type "{}".'.format(kind))
+                raise ValueError('This WCS does not have axis of type "{}".'.format(axis_type))
             result = np.asarray([(r.min(), r.max()) for r in result[axtyp_ind]])
 
-            if kind == "spatial":
+            if axis_type == "spatial":
                 result = _order_clockwise(result)
             else:
                 result.sort()