From 14d9fc5d976bd2a59cd37f7f9a2ff0d0911a38fd Mon Sep 17 00:00:00 2001
From: niksirbi <niko.sirbiladze@gmail.com>
Date: Thu, 29 Aug 2024 11:59:20 +0100
Subject: [PATCH] constrain kinematic functions to cartesian coordinates

---
 movement/analysis/kinematics.py | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/movement/analysis/kinematics.py b/movement/analysis/kinematics.py
index c9538787..3479de02 100644
--- a/movement/analysis/kinematics.py
+++ b/movement/analysis/kinematics.py
@@ -18,8 +18,8 @@ def compute_displacement(data: xr.DataArray) -> xr.DataArray:
     Parameters
     ----------
     data : xarray.DataArray
-        The input data containing position information, with
-        ``time`` as a dimension.
+        The input data containing position information, with ``time``
+        and ``space`` (in Cartesian coordinates) as required dimensions.
 
     Returns
     -------
@@ -27,7 +27,7 @@ def compute_displacement(data: xr.DataArray) -> xr.DataArray:
         An xarray DataArray containing the computed displacement.
 
     """
-    validate_dimension_coordinates(data, {"time": []})
+    validate_dimension_coordinates(data, {"time": [], "space": ["x", "y"]})
     result = data.diff(dim="time")
     result = result.reindex(data.coords, fill_value=0)
     return result
@@ -43,8 +43,8 @@ def compute_velocity(data: xr.DataArray) -> xr.DataArray:
     Parameters
     ----------
     data : xarray.DataArray
-        The input data containing position information, with
-        ``time`` as a dimension.
+        The input data containing position information, with ``time``
+        and ``space`` (in Cartesian coordinates) as required dimensions.
 
     Returns
     -------
@@ -69,8 +69,8 @@ def compute_acceleration(data: xr.DataArray) -> xr.DataArray:
     Parameters
     ----------
     data : xarray.DataArray
-        The input data containing position information, with
-        ``time`` as a dimension.
+        The input data containing position information, with ``time``
+        and ``space`` (in Cartesian coordinates) as required dimensions.
 
     Returns
     -------
@@ -97,7 +97,8 @@ def _compute_approximate_time_derivative(
     Parameters
     ----------
     data : xarray.DataArray
-        The input data containing ``time`` as a dimension.
+        The input data containing ``time`` and ``space`` (in Cartesian
+        coordinates) as require dimensions.
     order : int
         The order of the derivative. 1 for velocity, 2 for
         acceleration. Value must be a positive integer.
@@ -114,7 +115,7 @@ def _compute_approximate_time_derivative(
         )
     if order <= 0:
         raise log_error(ValueError, "Order must be a positive integer.")
-    validate_dimension_coordinates(data, {"time": []})
+    validate_dimension_coordinates(data, {"time": [], "space": ["x", "y"]})
     result = data
     for _ in range(order):
         result = result.differentiate("time")