Update interpolators

Author: VeckoTheGecko

src/parcels/_compat.py

@@ -1,7 +1,7 @@
 """Import helpers for compatability between installations."""
 
 
-# for compat with v3 of parcels when users provide `initial=attrgetter("lon")` to a Variable
+# for compat with v3 of parcels when users provide `initial=attrgetter("...")` to a Variable
 # so that particle initial state matches another variable
 class _AttrgetterHelper:
     """

src/parcels/_core/field.py

@@ -389,7 +389,7 @@ def _assert_same_time_interval(fields: Sequence[Field]) -> None:
 
 def _get_positions(field: Field, time, z, y, x, particles, _ei) -> tuple[dict, dict]:
     """Initialize and populate particle_positions and grid_positions dictionaries"""
-    particle_positions = {"time": time, "z": z, "lat": y, "lon": x}
+    particle_positions = {"time": time, "z": z, "y": y, "x": x}
     grid_positions = {}
     grid_positions.update(_search_time_index(field, time))
     grid_positions.update(field.grid.search(z, y, x, ei=_ei))

src/parcels/interpolators/_uxinterpolators.py

@@ -171,7 +171,7 @@ def interp(
         u = vectorfield.U.interp_method.interp(particle_positions, grid_positions, vectorfield.U)
         v = vectorfield.V.interp_method.interp(particle_positions, grid_positions, vectorfield.V)
         if vectorfield.grid._mesh == "spherical":
-            u /= 1852 * 60 * np.cos(np.deg2rad(particle_positions["lat"]))
+            u /= 1852 * 60 * np.cos(np.deg2rad(particle_positions["y"]))
             v /= 1852 * 60
 
         if "3D" in vectorfield.vector_type:

src/parcels/interpolators/_xinterpolators.py

@@ -132,7 +132,7 @@ def interp(
         field: Field,
     ):
         """Returning the single value of a Constant Field (with a size=(1,1,1,1) array)"""
-        return field.data[0, 0, 0, 0].values * np.ones_like(particle_positions["lon"])
+        return field.data[0, 0, 0, 0].values * np.ones_like(particle_positions["x"])
 
 
 class XLinear_Velocity(VectorInterpolator):  # noqa:  N801
@@ -149,7 +149,7 @@ def interp(
         u = _xlinear.interp(particle_positions, grid_positions, vectorfield.U)
         v = _xlinear.interp(particle_positions, grid_positions, vectorfield.V)
         if vectorfield.grid._mesh == "spherical":
-            u /= 1852 * 60 * np.cos(np.deg2rad(particle_positions["lat"]))
+            u /= 1852 * 60 * np.cos(np.deg2rad(particle_positions["y"]))
             v /= 1852 * 60
 
         if vectorfield.W:
@@ -304,7 +304,7 @@ def _compute_corner_data(data, selection_dict) -> np.ndarray:
             v = v.compute()
 
         if grid._mesh == "spherical":
-            conversion = 1852 * 60.0 * np.cos(np.deg2rad(particle_positions["lat"]))
+            conversion = 1852 * 60.0 * np.cos(np.deg2rad(particle_positions["y"]))
             u /= conversion
             v /= conversion
 

tests/test_particleset_execute.py

@@ -332,7 +332,7 @@ def test_raise_general_error(): ...
 def test_errorinterpolation(fieldset):
     class NaNInterpolator(ScalarInterpolator):  # pragma: no cover
         def interp(self, particle_positions, grid_positions, field):
-            return np.nan * np.zeros_like(particle_positions["lon"])
+            return np.nan * np.zeros_like(particle_positions["x"])
 
     def SampleU(particles, fieldset):  # pragma: no cover
         fieldset.U[particles.time, particles.z, particles.y, particles.x, particles]