Drop the .move accessor (#322)

* replace accessor with MovementDataset dataclass

* moved pre-save validations inside save_poses module

* deleted accessor code and associated tests

* define dataset structure in modular classes

* updated stale docstring for _validate_dataset()

* remove mentions of the accessor from the getting started guide

* dropped accessor use in examples

* ignore linkcheck for opensource licenses

* Revert "ignore linkcheck for opensource licenses"

This reverts commit c8f3498.

* use ds.sizes instead of ds.dims to suppress warning

* Add references

* remove movement_dataset.py module

---------

Co-authored-by: lochhh <changhuan.lo@ucl.ac.uk>

docs/source/getting_started/movement_dataset.md

@@ -195,7 +195,7 @@ For example, you can:
 [data aggregation and broadcasting](xarray:user-guide/computation.html), and
 - use `xarray`'s built-in [plotting methods](xarray:user-guide/plotting.html).
 
-As an example, here's how you can use the `sel` method to select subsets of
+As an example, here's how you can use {meth}`xarray.Dataset.sel` to select subsets of
 data:
 
 ```python
@@ -223,55 +223,45 @@ position = ds.position.sel(
 )  # the output is a data array
 ```
 
-### Accessing movement-specific functionality
+### Modifying movement datasets
 
-`movement` extends `xarray`'s functionality with a number of convenience
-methods that are specific to `movement` datasets. These `movement`-specific methods are accessed using the
-`move` keyword.
+Datasets can be modified by adding new **data variables** and **attributes**,
+or updating existing ones.
 
-For example, to compute the velocity and acceleration vectors for all individuals and keypoints across time, we provide the `move.compute_velocity` and `move.compute_acceleration` methods:
+Let's imagine we want to compute the instantaneous velocity of all tracked
+points and store the results within the same dataset, for convenience.
 
 ```python
-velocity = ds.move.compute_velocity()
-acceleration = ds.move.compute_acceleration()
-```
+from movement.analysis.kinematics import compute_velocity
 
-The `movement`-specific functionalities are implemented in the
-{class}`movement.move_accessor.MovementDataset` class, which is an [accessor](https://docs.xarray.dev/en/stable/internals/extending-xarray.html) to the
-underlying {class}`xarray.Dataset` object. Defining a custom accessor is convenient
-to avoid conflicts with `xarray`'s built-in methods.
+# compute velocity from position
+velocity = compute_velocity(ds.position)
+# add it to the dataset as a new data variable
+ds["velocity"] = velocity
 
-### Modifying movement datasets
+# we could have also done both steps in a single line
+ds["velocity"] = compute_velocity(ds.position)
 
-The `velocity` and `acceleration` produced in the above example are {class}`xarray.DataArray` objects, with the same **dimensions** as the
-original `position` **data variable**.
+# we can now access velocity like any other data variable
+ds.velocity
+```
 
-In some cases, you may wish to
-add these or other new **data variables** to the `movement` dataset for
-convenience. This can be done by simply assigning them to the dataset
-with an appropriate name:
+The output of {func}`movement.analysis.kinematics.compute_velocity` is an {class}`xarray.DataArray` object,
+with the same **dimensions** as the original `position` **data variable**,
+so adding it to the existing `ds` makes sense and works seamlessly.
 
-```python
-ds["velocity"] = velocity
-ds["acceleration"] = acceleration
+We can also update existing **data variables** in-place, using {meth}`xarray.Dataset.update`. For example, if we wanted to update the `position`
+and `velocity` arrays in our dataset, we could do:
 
-# we can now access these using dot notation on the dataset
-ds.velocity
-ds.acceleration
+```python
+ds.update({"position": position_filtered, "velocity": velocity_filtered})
 ```
 
-Custom **attributes** can also be added to the dataset:
+Custom **attributes** can be added to the dataset with:
 
 ```python
 ds.attrs["my_custom_attribute"] = "my_custom_value"
 
 # we can now access this value using dot notation on the dataset
 ds.my_custom_attribute
 ```
-
-We can also update existing **data variables** in-place, using the `update()` method. For example, if we wanted to update the `position`
-and `velocity` arrays in our dataset, we could do:
-
-```python
-ds.update({"position": position_filtered, "velocity": velocity_filtered})
-```

examples/compute_kinematics.py

@@ -117,27 +117,22 @@
 # %%
 # Compute displacement
 # ---------------------
+# The :mod:`movement.analysis.kinematics` module provides functions to compute
+# various kinematic quantities,
+# such as displacement, velocity, and acceleration.
 # We can start off by computing the distance travelled by the mice along
-# their trajectories.
-# For this, we can use the ``compute_displacement`` method of the
-# ``move`` accessor.
-displacement = ds.move.compute_displacement()
+# their trajectories:
 
-# %%
-# This method will return a data array equivalent to the ``position`` one,
-# but holding displacement data along the ``space`` axis, rather than
-# position data.
-
-# %%
-# Notice that we could also compute the displacement (and all the other
-# kinematic variables) using the :mod:`movement.analysis.kinematics` module:
-
-# %%
 import movement.analysis.kinematics as kin
 
-displacement_kin = kin.compute_displacement(position)
+displacement = kin.compute_displacement(position)
 
 # %%
+# The :func:`movement.analysis.kinematics.compute_displacement`
+# function will return a data array equivalent to the ``position`` one,
+# but holding displacement data along the ``space`` axis, rather than
+# position data.
+#
 # The ``displacement`` data array holds, for a given individual and keypoint
 # at timestep ``t``, the vector that goes from its previous position at time
 # ``t-1`` to its current position at time ``t``.
@@ -271,13 +266,14 @@
 # ----------------
 # We can easily compute the velocity vectors for all individuals in our data
 # array:
-velocity = ds.move.compute_velocity()
+velocity = kin.compute_velocity(position)
 
 # %%
-# The ``velocity`` method will return a data array equivalent to the
-# ``position`` one, but holding velocity data along the ``space`` axis, rather
-# than position data. Notice how ``xarray`` nicely deals with the different
-# individuals and spatial dimensions for us! ✨
+# The :func:`movement.analysis.kinematics.compute_velocity`
+# function will return a data array equivalent to
+# the ``position`` one, but holding velocity data along the ``space`` axis,
+# rather than position data. Notice how ``xarray`` nicely deals with the
+# different individuals and spatial dimensions for us! ✨
 
 # %%
 # We can plot the components of the velocity vector against time
@@ -350,8 +346,9 @@
 # %%
 # Compute acceleration
 # ---------------------
-# We can compute the acceleration of the data with an equivalent method:
-accel = ds.move.compute_acceleration()
+# Let's now compute the acceleration for all individuals in our data
+# array:
+accel = kin.compute_acceleration(position)
 
 # %%
 # and plot of the components of the acceleration vector ``ax``, ``ay`` per
@@ -375,8 +372,8 @@
 fig.tight_layout()
 
 # %%
-# The can also represent the magnitude (norm) of the acceleration vector
-# for each individual:
+# We can also compute and visualise the magnitude (norm) of the
+# acceleration vector for each individual:
 fig, axes = plt.subplots(3, 1, sharex=True, sharey=True)
 for mouse_name, ax in zip(accel.individuals.values, axes, strict=False):
     # compute magnitude of the acceleration vector for one mouse

examples/filter_and_interpolate.py

@@ -9,6 +9,8 @@
 # Imports
 # -------
 from movement import sample_data
+from movement.analysis.kinematics import compute_velocity
+from movement.filtering import filter_by_confidence, interpolate_over_time
 
 # %%
 # Load a sample dataset
@@ -73,35 +75,19 @@
 # %%
 # Filter out points with low confidence
 # -------------------------------------
-# Using the
-# :meth:`filter_by_confidence()\
-# <movement.move_accessor.MovementDataset.filtering_wrapper>`
-# method of the ``move`` accessor,
-# we can filter out points with confidence scores below a certain threshold.
-# The default ``threshold=0.6`` will be used when ``threshold`` is not
-# provided.
-# This method will also report the number of NaN values in the dataset before
-# and after the filtering operation by default (``print_report=True``).
+# Using the :func:`movement.filtering.filter_by_confidence` function from the
+# :mod:`movement.filtering` module, we can filter out points with confidence
+# scores below a certain threshold. This function takes ``position`` and
+# ``confidence`` as required arguments, and accepts an optional ``threshold``
+# parameter, which defaults to ``threshold=0.6`` unless specified otherwise.
+# The function will also report the number of NaN values in the dataset before
+# and after the filtering operation by default, but you can disable this
+# by passing ``print_report=False``.
+#
 # We will use :meth:`xarray.Dataset.update` to update ``ds`` in-place
 # with the filtered ``position``.
 
-ds.update({"position": ds.move.filter_by_confidence()})
-
-# %%
-# .. note::
-#    The ``move`` accessor :meth:`filter_by_confidence()\
-#    <movement.move_accessor.MovementDataset.filtering_wrapper>`
-#    method is a convenience method that applies
-#    :func:`movement.filtering.filter_by_confidence`,
-#    which takes ``position`` and ``confidence`` as arguments.
-#    The equivalent function call using the
-#    :mod:`movement.filtering` module would be:
-#
-#    .. code-block:: python
-#
-#       from movement.filtering import filter_by_confidence
-#
-#       ds.update({"position": filter_by_confidence(position, confidence)})
+ds.update({"position": filter_by_confidence(ds.position, ds.confidence)})
 
 # %%
 # We can see that the filtering operation has introduced NaN values in the
@@ -120,36 +106,16 @@
 # %%
 # Interpolate over missing values
 # -------------------------------
-# Using the
-# :meth:`interpolate_over_time()\
-# <movement.move_accessor.MovementDataset.filtering_wrapper>`
-# method of the ``move`` accessor,
-# we can interpolate over the gaps we've introduced in the pose tracks.
+# Using the :func:`movement.filtering.interpolate_over_time` function from the
+# :mod:`movement.filtering` module, we can interpolate over gaps
+# we've introduced in the pose tracks.
 # Here we use the default linear interpolation method (``method=linear``)
 # and interpolate over gaps of 40 frames or less (``max_gap=40``).
 # The default ``max_gap=None`` would interpolate over all gaps, regardless of
 # their length, but this should be used with caution as it can introduce
 # spurious data. The ``print_report`` argument acts as described above.
 
-ds.update({"position": ds.move.interpolate_over_time(max_gap=40)})
-
-# %%
-# .. note::
-#    The ``move`` accessor :meth:`interpolate_over_time()\
-#    <movement.move_accessor.MovementDataset.filtering_wrapper>`
-#    is also a convenience method that applies
-#    :func:`movement.filtering.interpolate_over_time`
-#    to the ``position`` data variable.
-#    The equivalent function call using the
-#    :mod:`movement.filtering` module would be:
-#
-#    .. code-block:: python
-#
-#       from movement.filtering import interpolate_over_time
-#
-#       ds.update({"position": interpolate_over_time(
-#           position_filtered, max_gap=40
-#       )})
+ds.update({"position": interpolate_over_time(ds.position, max_gap=40)})
 
 # %%
 # We see that all NaN values have disappeared, meaning that all gaps were
@@ -176,27 +142,25 @@
 # %%
 # Filtering multiple data variables
 # ---------------------------------
-# All :mod:`movement.filtering` functions are available via the
-# ``move`` accessor. These ``move`` accessor methods operate on the
-# ``position`` data variable in the dataset ``ds`` by default.
-# There is also an additional argument ``data_vars`` that allows us to
-# specify which data variables in ``ds`` to filter.
-# When multiple data variable names are specified in ``data_vars``,
-# the method will return a dictionary with the data variable names as keys
-# and the filtered DataArrays as values, otherwise it will return a single
-# DataArray that is the filtered data.
-# This is useful when we want to apply the same filtering operation to
+# We can also apply the same filtering operation to
 # multiple data variables in ``ds`` at the same time.
 #
 # For instance, to filter both ``position`` and ``velocity`` data variables
-# in ``ds``, based on the confidence scores, we can specify
-# ``data_vars=["position", "velocity"]`` in the method call.
-# As the filtered data variables are returned as a dictionary, we can once
-# again use :meth:`xarray.Dataset.update` to update ``ds`` in-place
+# in ``ds``, based on the confidence scores, we can specify a dictionary
+# with the data variable names as keys and the corresponding filtered
+# DataArrays as values. Then we can once again use
+# :meth:`xarray.Dataset.update`  to update ``ds`` in-place
 # with the filtered data variables.
 
-ds["velocity"] = ds.move.compute_velocity()
-filtered_data_dict = ds.move.filter_by_confidence(
-    data_vars=["position", "velocity"]
-)
-ds.update(filtered_data_dict)
+# Add velocity data variable to the dataset
+ds["velocity"] = compute_velocity(ds.position)
+
+# Create a dictionary mapping data variable names to filtered DataArrays
+# We disable report printing for brevity
+update_dict = {
+    var: filter_by_confidence(ds[var], ds.confidence, print_report=False)
+    for var in ["position", "velocity"]
+}
+
+# Use the dictionary to update the dataset in-place
+ds.update(update_dict)