From 86cf568651617345bfb57588064faca9e04cf6ae Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Thu, 2 Jan 2025 16:09:20 -0600
Subject: [PATCH 01/16] Initial Work

---
 test/test_subset.py             | 25 +++++++++++++++++++++++--
 uxarray/grid/grid.py            | 26 ++++++++++++++++++++++----
 uxarray/grid/slice.py           | 16 ++++++++++------
 uxarray/subset/grid_accessor.py | 27 ++++++++++++++++++---------
 4 files changed, 73 insertions(+), 21 deletions(-)

diff --git a/test/test_subset.py b/test/test_subset.py
index a1bfaed7f..2d5452fbe 100644
--- a/test/test_subset.py
+++ b/test/test_subset.py
@@ -104,8 +104,6 @@ def test_grid_bounding_box_subset():
                 bbox_antimeridian[0], bbox_antimeridian[1], element=element)
 
 
-
-
 def test_uxda_isel():
     uxds = ux.open_dataset(GRID_PATHS[0], DATA_PATHS[0])
 
@@ -113,6 +111,7 @@ def test_uxda_isel():
 
     assert len(sub) == 3
 
+
 def test_uxda_isel_with_coords():
     uxds = ux.open_dataset(GRID_PATHS[0], DATA_PATHS[0])
     uxds = uxds.assign_coords({"lon_face": uxds.uxgrid.face_lon})
@@ -120,3 +119,25 @@ def test_uxda_isel_with_coords():
 
     assert "lon_face" in sub.coords
     assert len(sub.coords['lon_face']) == 3
+
+
+def test_inverse_face_indices():
+    grid = ux.open_grid(GRID_PATHS[0])
+
+    # Test nearest neighbor subsetting
+    coord = [0, 0]
+    subset = grid.subset.nearest_neighbor(coord, k=1, element="face centers", inverse_indices=True)
+
+    assert subset.inverse_face_indices is not None
+
+    # Test bounding box subsetting
+    box = [(-10, 10), (-10, 10)]
+    subset = grid.subset.bounding_box(box[0], box[1], element="edge centers", inverse_indices=True)
+
+    assert subset.inverse_face_indices is not None
+
+    # Test bounding circle subsetting
+    center_coord = [0, 0]
+    subset = grid.subset.bounding_circle(center_coord, r=10, element="nodes", inverse_indices=True)
+
+    assert subset.inverse_face_indices is not None
diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index e1bac7d24..7bedb343e 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -1506,6 +1506,18 @@ def global_sphere_coverage(self):
         (i.e. contains no holes)"""
         return not self.partial_sphere_coverage
 
+    @property
+    def inverse_face_indices(self):
+        if self._is_subset:
+            return self._ds["inverse_face_indices"]
+
+    @property
+    def _is_subset(self):
+        """Boolean indicator for whether the Grid is from a subset or not."""
+        if "_is_subset" not in self._ds:
+            self._ds["_is_subset"] = False
+        return self._ds["_is_subset"]
+
     def chunk(self, n_node="auto", n_edge="auto", n_face="auto"):
         """Converts all arrays to dask arrays with given chunks across grid
         dimensions in-place.
@@ -2201,7 +2213,7 @@ def get_dual(self):
 
         return dual
 
-    def isel(self, **dim_kwargs):
+    def isel(self, inverse_indices=False, **dim_kwargs):
         """Indexes an unstructured grid along a given dimension (``n_node``,
         ``n_edge``, or ``n_face``) and returns a new grid.
 
@@ -2226,13 +2238,19 @@ def isel(self, **dim_kwargs):
             raise ValueError("Indexing must be along a single dimension.")
 
         if "n_node" in dim_kwargs:
-            return _slice_node_indices(self, dim_kwargs["n_node"])
+            return _slice_node_indices(
+                self, dim_kwargs["n_node"], inverse_indices=inverse_indices
+            )
 
         elif "n_edge" in dim_kwargs:
-            return _slice_edge_indices(self, dim_kwargs["n_edge"])
+            return _slice_edge_indices(
+                self, dim_kwargs["n_edge"], inverse_indices=inverse_indices
+            )
 
         elif "n_face" in dim_kwargs:
-            return _slice_face_indices(self, dim_kwargs["n_face"])
+            return _slice_face_indices(
+                self, dim_kwargs["n_face"], inverse_indices=inverse_indices
+            )
 
         else:
             raise ValueError(
diff --git a/uxarray/grid/slice.py b/uxarray/grid/slice.py
index bc660332e..430389ba8 100644
--- a/uxarray/grid/slice.py
+++ b/uxarray/grid/slice.py
@@ -10,7 +10,7 @@
     pass
 
 
-def _slice_node_indices(grid, indices, inclusive=True):
+def _slice_node_indices(grid, indices, inclusive=True, inverse_indices=False):
     """Slices (indexes) an unstructured grid given a list/array of node
     indices, returning a new Grid composed of elements that contain the nodes
     specified in the indices.
@@ -33,10 +33,10 @@ def _slice_node_indices(grid, indices, inclusive=True):
     face_indices = np.unique(grid.node_face_connectivity.values[indices].ravel())
     face_indices = face_indices[face_indices != INT_FILL_VALUE]
 
-    return _slice_face_indices(grid, face_indices)
+    return _slice_face_indices(grid, face_indices, inverse_indices=inverse_indices)
 
 
-def _slice_edge_indices(grid, indices, inclusive=True):
+def _slice_edge_indices(grid, indices, inclusive=True, inverse_indices=False):
     """Slices (indexes) an unstructured grid given a list/array of edge
     indices, returning a new Grid composed of elements that contain the edges
     specified in the indices.
@@ -59,10 +59,10 @@ def _slice_edge_indices(grid, indices, inclusive=True):
     face_indices = np.unique(grid.edge_face_connectivity.values[indices].ravel())
     face_indices = face_indices[face_indices != INT_FILL_VALUE]
 
-    return _slice_face_indices(grid, face_indices)
+    return _slice_face_indices(grid, face_indices, inverse_indices=inverse_indices)
 
 
-def _slice_face_indices(grid, indices, inclusive=True):
+def _slice_face_indices(grid, indices, inclusive=True, inverse_indices=False):
     """Slices (indexes) an unstructured grid given a list/array of face
     indices, returning a new Grid composed of elements that contain the faces
     specified in the indices.
@@ -77,7 +77,6 @@ def _slice_face_indices(grid, indices, inclusive=True):
         Whether to perform inclusive (i.e. elements must contain at least one desired feature from a slice) as opposed
         to exclusive (i.e elements be made up all desired features from a slice)
     """
-
     if inclusive is False:
         raise ValueError("Exclusive slicing is not yet supported.")
 
@@ -132,4 +131,9 @@ def _slice_face_indices(grid, indices, inclusive=True):
             # drop any conn that would require re-computation
             ds = ds.drop_vars(conn_name)
 
+    if inverse_indices:
+        ds["inverse_face_indices"] = indices
+
+    ds["_is_subset"] = True
+
     return Grid.from_dataset(ds, source_grid_spec=grid.source_grid_spec)
diff --git a/uxarray/subset/grid_accessor.py b/uxarray/subset/grid_accessor.py
index 60dc8c800..c80686228 100644
--- a/uxarray/subset/grid_accessor.py
+++ b/uxarray/subset/grid_accessor.py
@@ -33,6 +33,7 @@ def bounding_box(
         lat_bounds: Union[Tuple, List, np.ndarray],
         element: Optional[str] = "nodes",
         method: Optional[str] = "coords",
+        inverse_indices=False,
         **kwargs,
     ):
         """Subsets an unstructured grid between two latitude and longitude
@@ -53,6 +54,8 @@ def bounding_box(
             face centers, or edge centers lie within the bounds.
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
+        inverse_indices : bool
+            Flag to indicate whether to store the original grids face indices for later use
         """
 
         if method == "coords":
@@ -101,11 +104,11 @@ def bounding_box(
                 )
 
             if element == "nodes":
-                return self.uxgrid.isel(n_node=indices)
+                return self.uxgrid.isel(inverse_indices, n_node=indices)
             elif element == "face centers":
-                return self.uxgrid.isel(n_face=indices)
+                return self.uxgrid.isel(inverse_indices, n_face=indices)
             elif element == "edge centers":
-                return self.uxgrid.isel(n_edge=indices)
+                return self.uxgrid.isel(inverse_indices, n_edge=indices)
 
         else:
             raise ValueError(f"Method '{method}' not supported.")
@@ -115,6 +118,7 @@ def bounding_circle(
         center_coord: Union[Tuple, List, np.ndarray],
         r: Union[float, int],
         element: Optional[str] = "nodes",
+        inverse_indices=False,
         **kwargs,
     ):
         """Subsets an unstructured grid by returning all elements within some
@@ -128,6 +132,8 @@ def bounding_circle(
             Radius of bounding circle (in degrees)
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
+        inverse_indices : bool
+            Flag to indicate whether to store the original grids face indices for later use
         """
 
         coords = np.asarray(center_coord)
@@ -141,13 +147,14 @@ def bounding_circle(
                 f"No elements founding within the bounding circle with radius {r} when querying {element}"
             )
 
-        return self._index_grid(ind, element)
+        return self._index_grid(ind, element, inverse_indices)
 
     def nearest_neighbor(
         self,
         center_coord: Union[Tuple, List, np.ndarray],
         k: int,
         element: Optional[str] = "nodes",
+        inverse_indices=False,
         **kwargs,
     ):
         """Subsets an unstructured grid by returning the ``k`` closest
@@ -161,6 +168,8 @@ def nearest_neighbor(
             Number of neighbors to query
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
+        inverse_indices : bool
+            Flag to indicate whether to store the original grids face indices for later use
         """
 
         coords = np.asarray(center_coord)
@@ -169,7 +178,7 @@ def nearest_neighbor(
 
         _, ind = tree.query(coords, k)
 
-        return self._index_grid(ind, element)
+        return self._index_grid(ind, element, inverse_indices=inverse_indices)
 
     def _get_tree(self, coords, tree_type):
         """Internal helper for obtaining the desired KDTree or BallTree."""
@@ -187,12 +196,12 @@ def _get_tree(self, coords, tree_type):
 
         return tree
 
-    def _index_grid(self, ind, tree_type):
+    def _index_grid(self, ind, tree_type, inverse_indices=False):
         """Internal helper for indexing a grid with indices based off the
         provided tree type."""
         if tree_type == "nodes":
-            return self.uxgrid.isel(n_node=ind)
+            return self.uxgrid.isel(inverse_indices, n_node=ind)
         elif tree_type == "edge centers":
-            return self.uxgrid.isel(n_edge=ind)
+            return self.uxgrid.isel(inverse_indices, n_edge=ind)
         else:
-            return self.uxgrid.isel(n_face=ind)
+            return self.uxgrid.isel(inverse_indices, n_face=ind)

From 5f6285d4322581e004058e8b62528cb2d266d597 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Fri, 3 Jan 2025 09:30:07 -0600
Subject: [PATCH 02/16] Addressed review comments

---
 uxarray/grid/grid.py  | 22 ++++++++++++----------
 uxarray/grid/slice.py |  4 +---
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index 7bedb343e..8e2a64775 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -160,6 +160,7 @@ def __init__(
         grid_ds: xr.Dataset,
         source_grid_spec: Optional[str] = None,
         source_dims_dict: Optional[dict] = {},
+        is_subset=False,
     ):
         # check if inputted dataset is a minimum representable 2D UGRID unstructured grid
         if not _validate_minimum_ugrid(grid_ds):
@@ -191,6 +192,7 @@ def __init__(
         # initialize attributes
         self._antimeridian_face_indices = None
         self._ds.assign_attrs({"source_grid_spec": self.source_grid_spec})
+        self.is_subset = is_subset
 
         # cached parameters for GeoDataFrame conversions
         self._gdf_cached_parameters = {
@@ -242,7 +244,9 @@ def __init__(
     cross_section = UncachedAccessor(GridCrossSectionAccessor)
 
     @classmethod
-    def from_dataset(cls, dataset, use_dual: Optional[bool] = False, **kwargs):
+    def from_dataset(
+        cls, dataset, use_dual: Optional[bool] = False, is_subset=False, **kwargs
+    ):
         """Constructs a ``Grid`` object from a dataset.
 
         Parameters
@@ -301,7 +305,7 @@ def from_dataset(cls, dataset, use_dual: Optional[bool] = False, **kwargs):
             except TypeError:
                 raise ValueError("Unsupported Grid Format")
 
-        return cls(grid_ds, source_grid_spec, source_dims_dict)
+        return cls(grid_ds, source_grid_spec, source_dims_dict, is_subset=is_subset)
 
     @classmethod
     def from_file(
@@ -1508,15 +1512,13 @@ def global_sphere_coverage(self):
 
     @property
     def inverse_face_indices(self):
-        if self._is_subset:
+        """Indices for a subset that map each face in the subset back to the original grid"""
+        if self.is_subset:
             return self._ds["inverse_face_indices"]
-
-    @property
-    def _is_subset(self):
-        """Boolean indicator for whether the Grid is from a subset or not."""
-        if "_is_subset" not in self._ds:
-            self._ds["_is_subset"] = False
-        return self._ds["_is_subset"]
+        else:
+            raise Exception(
+                "Grid is not a subset, therefore no inverse face indices exist"
+            )
 
     def chunk(self, n_node="auto", n_edge="auto", n_face="auto"):
         """Converts all arrays to dask arrays with given chunks across grid
diff --git a/uxarray/grid/slice.py b/uxarray/grid/slice.py
index 430389ba8..c748ce588 100644
--- a/uxarray/grid/slice.py
+++ b/uxarray/grid/slice.py
@@ -134,6 +134,4 @@ def _slice_face_indices(grid, indices, inclusive=True, inverse_indices=False):
     if inverse_indices:
         ds["inverse_face_indices"] = indices
 
-    ds["_is_subset"] = True
-
-    return Grid.from_dataset(ds, source_grid_spec=grid.source_grid_spec)
+    return Grid.from_dataset(ds, source_grid_spec=grid.source_grid_spec, is_subset=True)

From dcd717f23ef022a58e54dc36d9cf3e21192761be Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Fri, 3 Jan 2025 09:31:40 -0600
Subject: [PATCH 03/16] Updated doc string

---
 uxarray/grid/grid.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index 8e2a64775..36b239151 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -256,6 +256,8 @@ def from_dataset(
             containing ASCII files represents a FESOM2 grid.
         use_dual : bool, default=False
             When reading in MPAS formatted datasets, indicates whether to use the Dual Mesh
+        is_subset : bool, default=False
+            Bool flag to indicate whether a grid is a subset
         """
 
         if isinstance(dataset, xr.Dataset):

From d23058f60ae6ae638c864d26d41e7cc3fb97dcd4 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Fri, 3 Jan 2025 15:58:49 -0600
Subject: [PATCH 04/16] Added inverse_indices support for data arrays and cross
 sections

---
 uxarray/core/dataarray.py                    | 14 ++++++++++----
 uxarray/cross_sections/dataarray_accessor.py | 12 ++++++++----
 uxarray/cross_sections/grid_accessor.py      | 14 ++++++++++++--
 uxarray/subset/dataarray_accessor.py         | 15 ++++++++++++---
 4 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/uxarray/core/dataarray.py b/uxarray/core/dataarray.py
index 216b2309c..bfec83280 100644
--- a/uxarray/core/dataarray.py
+++ b/uxarray/core/dataarray.py
@@ -1035,7 +1035,7 @@ def _edge_centered(self) -> bool:
         "n_edge" dimension)"""
         return "n_edge" in self.dims
 
-    def isel(self, ignore_grid=False, *args, **kwargs):
+    def isel(self, ignore_grid=False, inverse_indices=False, *args, **kwargs):
         """Grid-informed implementation of xarray's ``isel`` method, which
         enables indexing across grid dimensions.
 
@@ -1069,11 +1069,17 @@ def isel(self, ignore_grid=False, *args, **kwargs):
                 raise ValueError("Only one grid dimension can be sliced at a time")
 
             if "n_node" in kwargs:
-                sliced_grid = self.uxgrid.isel(n_node=kwargs["n_node"])
+                sliced_grid = self.uxgrid.isel(
+                    n_node=kwargs["n_node"], inverse_indices=inverse_indices
+                )
             elif "n_edge" in kwargs:
-                sliced_grid = self.uxgrid.isel(n_edge=kwargs["n_edge"])
+                sliced_grid = self.uxgrid.isel(
+                    n_edge=kwargs["n_edge"], inverse_indices=inverse_indices
+                )
             else:
-                sliced_grid = self.uxgrid.isel(n_face=kwargs["n_face"])
+                sliced_grid = self.uxgrid.isel(
+                    n_face=kwargs["n_face"], inverse_indices=inverse_indices
+                )
 
             return self._slice_from_grid(sliced_grid)
 
diff --git a/uxarray/cross_sections/dataarray_accessor.py b/uxarray/cross_sections/dataarray_accessor.py
index 6f82a8f2e..0c9166fe6 100644
--- a/uxarray/cross_sections/dataarray_accessor.py
+++ b/uxarray/cross_sections/dataarray_accessor.py
@@ -22,7 +22,7 @@ def __repr__(self):
 
         return prefix + methods_heading
 
-    def constant_latitude(self, lat: float):
+    def constant_latitude(self, lat: float, inverse_indices: bool = False):
         """Extracts a cross-section of the data array by selecting all faces that
         intersect with a specified line of constant latitude.
 
@@ -31,6 +31,8 @@ def constant_latitude(self, lat: float):
         lat : float
             The latitude at which to extract the cross-section, in degrees.
             Must be between -90.0 and 90.0
+        inverse_indices : bool, optional
+            If True, stores the original grid indices
 
         Returns
         -------
@@ -60,9 +62,9 @@ def constant_latitude(self, lat: float):
 
         faces = self.uxda.uxgrid.get_faces_at_constant_latitude(lat)
 
-        return self.uxda.isel(n_face=faces)
+        return self.uxda.isel(n_face=faces, inverse_indices=inverse_indices)
 
-    def constant_longitude(self, lon: float):
+    def constant_longitude(self, lon: float, inverse_indices: bool = False):
         """Extracts a cross-section of the data array by selecting all faces that
         intersect with a specified line of constant longitude.
 
@@ -71,6 +73,8 @@ def constant_longitude(self, lon: float):
         lon : float
             The latitude at which to extract the cross-section, in degrees.
             Must be between -180.0 and 180.0
+        inverse_indices : bool, optional
+            If True, stores the original grid indices
 
         Returns
         -------
@@ -102,7 +106,7 @@ def constant_longitude(self, lon: float):
             lon,
         )
 
-        return self.uxda.isel(n_face=faces)
+        return self.uxda.isel(n_face=faces, inverse_indices=inverse_indices)
 
     def gca(self, *args, **kwargs):
         raise NotImplementedError
diff --git a/uxarray/cross_sections/grid_accessor.py b/uxarray/cross_sections/grid_accessor.py
index ee30bd913..4b9ce82f2 100644
--- a/uxarray/cross_sections/grid_accessor.py
+++ b/uxarray/cross_sections/grid_accessor.py
@@ -25,6 +25,7 @@ def constant_latitude(
         self,
         lat: float,
         return_face_indices: bool = False,
+        inverse_indices: bool = False,
     ):
         """Extracts a cross-section of the grid by selecting all faces that
         intersect with a specified line of constant latitude.
@@ -36,6 +37,8 @@ def constant_latitude(
             Must be between -90.0 and 90.0
         return_face_indices : bool, optional
             If True, also returns the indices of the faces that intersect with the line of constant latitude.
+        inverse_indices : bool, optional
+            If True, stores the original grid indices
 
         Returns
         -------
@@ -66,7 +69,9 @@ def constant_latitude(
         if len(faces) == 0:
             raise ValueError(f"No intersections found at lat={lat}.")
 
-        grid_at_constant_lat = self.uxgrid.isel(n_face=faces)
+        grid_at_constant_lat = self.uxgrid.isel(
+            n_face=faces, inverse_indices=inverse_indices
+        )
 
         if return_face_indices:
             return grid_at_constant_lat, faces
@@ -77,6 +82,7 @@ def constant_longitude(
         self,
         lon: float,
         return_face_indices: bool = False,
+        inverse_indices: bool = False,
     ):
         """Extracts a cross-section of the grid by selecting all faces that
         intersect with a specified line of constant longitude.
@@ -88,6 +94,8 @@ def constant_longitude(
             Must be between -90.0 and 90.0
         return_face_indices : bool, optional
             If True, also returns the indices of the faces that intersect with the line of constant longitude.
+        inverse_indices : bool, optional
+            If True, stores the original grid indices
 
         Returns
         -------
@@ -117,7 +125,9 @@ def constant_longitude(
         if len(faces) == 0:
             raise ValueError(f"No intersections found at lon={lon}")
 
-        grid_at_constant_lon = self.uxgrid.isel(n_face=faces)
+        grid_at_constant_lon = self.uxgrid.isel(
+            n_face=faces, inverse_indices=inverse_indices
+        )
 
         if return_face_indices:
             return grid_at_constant_lon, faces
diff --git a/uxarray/subset/dataarray_accessor.py b/uxarray/subset/dataarray_accessor.py
index 3624e1e3e..b058505e6 100644
--- a/uxarray/subset/dataarray_accessor.py
+++ b/uxarray/subset/dataarray_accessor.py
@@ -33,6 +33,7 @@ def bounding_box(
         lat_bounds: Union[Tuple, List, np.ndarray],
         element: Optional[str] = "nodes",
         method: Optional[str] = "coords",
+        inverse_indices=False,
         **kwargs,
     ):
         """Subsets an unstructured grid between two latitude and longitude
@@ -53,9 +54,11 @@ def bounding_box(
             face centers, or edge centers lie within the bounds.
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
+        inverse_indices : bool
+            Flag to indicate whether to store the original grids face indices for later use
         """
         grid = self.uxda.uxgrid.subset.bounding_box(
-            lon_bounds, lat_bounds, element, method
+            lon_bounds, lat_bounds, element, method, inverse_indices=inverse_indices
         )
 
         return self.uxda._slice_from_grid(grid)
@@ -65,6 +68,7 @@ def bounding_circle(
         center_coord: Union[Tuple, List, np.ndarray],
         r: Union[float, int],
         element: Optional[str] = "nodes",
+        inverse_indices=False,
         **kwargs,
     ):
         """Subsets an unstructured grid by returning all elements within some
@@ -78,9 +82,11 @@ def bounding_circle(
             Radius of bounding circle (in degrees)
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
+        inverse_indices : bool
+            Flag to indicate whether to store the original grids face indices for later use
         """
         grid = self.uxda.uxgrid.subset.bounding_circle(
-            center_coord, r, element, **kwargs
+            center_coord, r, element, inverse_indices=inverse_indices**kwargs
         )
         return self.uxda._slice_from_grid(grid)
 
@@ -89,6 +95,7 @@ def nearest_neighbor(
         center_coord: Union[Tuple, List, np.ndarray],
         k: int,
         element: Optional[str] = "nodes",
+        inverse_indices=False,
         **kwargs,
     ):
         """Subsets an unstructured grid by returning the ``k`` closest
@@ -102,10 +109,12 @@ def nearest_neighbor(
             Number of neighbors to query
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
+        inverse_indices : bool
+            Flag to indicate whether to store the original grids face indices for later use
         """
 
         grid = self.uxda.uxgrid.subset.nearest_neighbor(
-            center_coord, k, element, **kwargs
+            center_coord, k, element, inverse_indices=inverse_indices, **kwargs
         )
 
         return self.uxda._slice_from_grid(grid)

From ae151aacf94ea7ec5ac3fe90aceb9758177dd6d4 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Mon, 6 Jan 2025 13:41:27 -0600
Subject: [PATCH 05/16] Added ability to choose which inverse_indices to store,
 stores as ds

---
 test/test_subset.py                          | 14 ++++---
 uxarray/cross_sections/dataarray_accessor.py | 10 +++--
 uxarray/cross_sections/grid_accessor.py      |  6 +--
 uxarray/grid/grid.py                         | 39 +++++++++++++----
 uxarray/grid/slice.py                        | 44 +++++++++++++++++---
 uxarray/subset/dataarray_accessor.py         | 10 ++---
 uxarray/subset/grid_accessor.py              |  8 ++--
 7 files changed, 99 insertions(+), 32 deletions(-)

diff --git a/test/test_subset.py b/test/test_subset.py
index 2d5452fbe..b5fa2fda7 100644
--- a/test/test_subset.py
+++ b/test/test_subset.py
@@ -128,16 +128,20 @@ def test_inverse_face_indices():
     coord = [0, 0]
     subset = grid.subset.nearest_neighbor(coord, k=1, element="face centers", inverse_indices=True)
 
-    assert subset.inverse_face_indices is not None
+    assert subset.inverse_indices is not None
 
     # Test bounding box subsetting
     box = [(-10, 10), (-10, 10)]
-    subset = grid.subset.bounding_box(box[0], box[1], element="edge centers", inverse_indices=True)
+    subset = grid.subset.bounding_box(box[0], box[1], element="face centers", inverse_indices=True)
 
-    assert subset.inverse_face_indices is not None
+    assert subset.inverse_indices is not None
 
     # Test bounding circle subsetting
     center_coord = [0, 0]
-    subset = grid.subset.bounding_circle(center_coord, r=10, element="nodes", inverse_indices=True)
+    subset = grid.subset.bounding_circle(center_coord, r=10, element="face centers", inverse_indices=True)
 
-    assert subset.inverse_face_indices is not None
+    assert subset.inverse_indices is not None
+
+    # Ensure code raises exceptions when the element is edges or nodes
+    assert pytest.raises(Exception, grid.subset.bounding_circle, center_coord, r=10, element="edge centers", inverse_indices=True)
+    assert pytest.raises(Exception, grid.subset.bounding_circle, center_coord, r=10, element="node centers", inverse_indices=True)
diff --git a/uxarray/cross_sections/dataarray_accessor.py b/uxarray/cross_sections/dataarray_accessor.py
index 0c9166fe6..48a864a74 100644
--- a/uxarray/cross_sections/dataarray_accessor.py
+++ b/uxarray/cross_sections/dataarray_accessor.py
@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Union, List, Set
 
 if TYPE_CHECKING:
     pass
@@ -22,7 +22,9 @@ def __repr__(self):
 
         return prefix + methods_heading
 
-    def constant_latitude(self, lat: float, inverse_indices: bool = False):
+    def constant_latitude(
+        self, lat: float, inverse_indices: Union[List[str], Set[str], bool] = False
+    ):
         """Extracts a cross-section of the data array by selecting all faces that
         intersect with a specified line of constant latitude.
 
@@ -64,7 +66,9 @@ def constant_latitude(self, lat: float, inverse_indices: bool = False):
 
         return self.uxda.isel(n_face=faces, inverse_indices=inverse_indices)
 
-    def constant_longitude(self, lon: float, inverse_indices: bool = False):
+    def constant_longitude(
+        self, lon: float, inverse_indices: Union[List[str], Set[str], bool] = False
+    ):
         """Extracts a cross-section of the data array by selecting all faces that
         intersect with a specified line of constant longitude.
 
diff --git a/uxarray/cross_sections/grid_accessor.py b/uxarray/cross_sections/grid_accessor.py
index 4b9ce82f2..36b91521a 100644
--- a/uxarray/cross_sections/grid_accessor.py
+++ b/uxarray/cross_sections/grid_accessor.py
@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Union, List, Set
 
 if TYPE_CHECKING:
     from uxarray.grid import Grid
@@ -25,7 +25,7 @@ def constant_latitude(
         self,
         lat: float,
         return_face_indices: bool = False,
-        inverse_indices: bool = False,
+        inverse_indices: Union[List[str], Set[str], bool] = False,
     ):
         """Extracts a cross-section of the grid by selecting all faces that
         intersect with a specified line of constant latitude.
@@ -82,7 +82,7 @@ def constant_longitude(
         self,
         lon: float,
         return_face_indices: bool = False,
-        inverse_indices: bool = False,
+        inverse_indices: Union[List[str], Set[str], bool] = False,
     ):
         """Extracts a cross-section of the grid by selecting all faces that
         intersect with a specified line of constant longitude.
diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index 36b239151..51a11f94e 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -9,6 +9,8 @@
 from typing import (
     Optional,
     Union,
+    List,
+    Set,
 )
 
 # reader and writer imports
@@ -161,6 +163,7 @@ def __init__(
         source_grid_spec: Optional[str] = None,
         source_dims_dict: Optional[dict] = {},
         is_subset=False,
+        inverse_indices: Optional[xr.Dataset] = None,
     ):
         # check if inputted dataset is a minimum representable 2D UGRID unstructured grid
         if not _validate_minimum_ugrid(grid_ds):
@@ -194,6 +197,9 @@ def __init__(
         self._ds.assign_attrs({"source_grid_spec": self.source_grid_spec})
         self.is_subset = is_subset
 
+        if inverse_indices is not None:
+            self.inverse_indices = inverse_indices
+
         # cached parameters for GeoDataFrame conversions
         self._gdf_cached_parameters = {
             "gdf": None,
@@ -244,9 +250,7 @@ def __init__(
     cross_section = UncachedAccessor(GridCrossSectionAccessor)
 
     @classmethod
-    def from_dataset(
-        cls, dataset, use_dual: Optional[bool] = False, is_subset=False, **kwargs
-    ):
+    def from_dataset(cls, dataset, use_dual: Optional[bool] = False, **kwargs):
         """Constructs a ``Grid`` object from a dataset.
 
         Parameters
@@ -307,7 +311,13 @@ def from_dataset(
             except TypeError:
                 raise ValueError("Unsupported Grid Format")
 
-        return cls(grid_ds, source_grid_spec, source_dims_dict, is_subset=is_subset)
+        return cls(
+            grid_ds,
+            source_grid_spec,
+            source_dims_dict,
+            is_subset=kwargs.get("is_subset", False),
+            inverse_indices=kwargs.get("inverse_indices"),
+        )
 
     @classmethod
     def from_file(
@@ -1513,15 +1523,20 @@ def global_sphere_coverage(self):
         return not self.partial_sphere_coverage
 
     @property
-    def inverse_face_indices(self):
+    def inverse_indices(self):
         """Indices for a subset that map each face in the subset back to the original grid"""
         if self.is_subset:
-            return self._ds["inverse_face_indices"]
+            return self._inverse_indices
         else:
             raise Exception(
                 "Grid is not a subset, therefore no inverse face indices exist"
             )
 
+    @inverse_indices.setter
+    def inverse_indices(self, value):
+        assert isinstance(value, xr.Dataset)
+        self._inverse_indices = value
+
     def chunk(self, n_node="auto", n_edge="auto", n_face="auto"):
         """Converts all arrays to dask arrays with given chunks across grid
         dimensions in-place.
@@ -2217,7 +2232,9 @@ def get_dual(self):
 
         return dual
 
-    def isel(self, inverse_indices=False, **dim_kwargs):
+    def isel(
+        self, inverse_indices: Union[List[str], Set[str], bool] = False, **dim_kwargs
+    ):
         """Indexes an unstructured grid along a given dimension (``n_node``,
         ``n_edge``, or ``n_face``) and returns a new grid.
 
@@ -2242,11 +2259,19 @@ def isel(self, inverse_indices=False, **dim_kwargs):
             raise ValueError("Indexing must be along a single dimension.")
 
         if "n_node" in dim_kwargs:
+            if inverse_indices:
+                raise Exception(
+                    "Inverse indices are not yet supported for node selection, please use face centers"
+                )
             return _slice_node_indices(
                 self, dim_kwargs["n_node"], inverse_indices=inverse_indices
             )
 
         elif "n_edge" in dim_kwargs:
+            if inverse_indices:
+                raise Exception(
+                    "Inverse indices are not yet supported for edge selection, please use face centers"
+                )
             return _slice_edge_indices(
                 self, dim_kwargs["n_edge"], inverse_indices=inverse_indices
             )
diff --git a/uxarray/grid/slice.py b/uxarray/grid/slice.py
index c748ce588..3f7416d84 100644
--- a/uxarray/grid/slice.py
+++ b/uxarray/grid/slice.py
@@ -4,13 +4,18 @@
 import xarray as xr
 from uxarray.constants import INT_FILL_VALUE, INT_DTYPE
 
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Union, List, Set
 
 if TYPE_CHECKING:
     pass
 
 
-def _slice_node_indices(grid, indices, inclusive=True, inverse_indices=False):
+def _slice_node_indices(
+    grid,
+    indices,
+    inclusive=True,
+    inverse_indices: Union[List[str], Set[str], bool] = False,
+):
     """Slices (indexes) an unstructured grid given a list/array of node
     indices, returning a new Grid composed of elements that contain the nodes
     specified in the indices.
@@ -36,7 +41,12 @@ def _slice_node_indices(grid, indices, inclusive=True, inverse_indices=False):
     return _slice_face_indices(grid, face_indices, inverse_indices=inverse_indices)
 
 
-def _slice_edge_indices(grid, indices, inclusive=True, inverse_indices=False):
+def _slice_edge_indices(
+    grid,
+    indices,
+    inclusive=True,
+    inverse_indices: Union[List[str], Set[str], bool] = False,
+):
     """Slices (indexes) an unstructured grid given a list/array of edge
     indices, returning a new Grid composed of elements that contain the edges
     specified in the indices.
@@ -62,7 +72,12 @@ def _slice_edge_indices(grid, indices, inclusive=True, inverse_indices=False):
     return _slice_face_indices(grid, face_indices, inverse_indices=inverse_indices)
 
 
-def _slice_face_indices(grid, indices, inclusive=True, inverse_indices=False):
+def _slice_face_indices(
+    grid,
+    indices,
+    inclusive=True,
+    inverse_indices: Union[List[str], Set[str], bool] = False,
+):
     """Slices (indexes) an unstructured grid given a list/array of face
     indices, returning a new Grid composed of elements that contain the faces
     specified in the indices.
@@ -132,6 +147,25 @@ def _slice_face_indices(grid, indices, inclusive=True, inverse_indices=False):
             ds = ds.drop_vars(conn_name)
 
     if inverse_indices:
-        ds["inverse_face_indices"] = indices
+        inverse_indices_ds = xr.Dataset()
+
+        index_types = {
+            "face centers": face_indices,
+            "edge centers": edge_indices,
+            "nodes": node_indices,
+        }
+        if isinstance(inverse_indices, bool):
+            inverse_indices_ds["face centers"] = face_indices
+        else:
+            for index_type in inverse_indices[0]:
+                if index_type in index_types:
+                    inverse_indices_ds[index_type] = index_types[index_type]
+
+        return Grid.from_dataset(
+            ds,
+            source_grid_spec=grid.source_grid_spec,
+            is_subset=True,
+            inverse_indices=inverse_indices_ds,
+        )
 
     return Grid.from_dataset(ds, source_grid_spec=grid.source_grid_spec, is_subset=True)
diff --git a/uxarray/subset/dataarray_accessor.py b/uxarray/subset/dataarray_accessor.py
index b058505e6..b71e78f08 100644
--- a/uxarray/subset/dataarray_accessor.py
+++ b/uxarray/subset/dataarray_accessor.py
@@ -2,7 +2,7 @@
 
 import numpy as np
 
-from typing import TYPE_CHECKING, Union, Tuple, List, Optional
+from typing import TYPE_CHECKING, Union, Tuple, List, Optional, Set
 
 if TYPE_CHECKING:
     pass
@@ -33,7 +33,7 @@ def bounding_box(
         lat_bounds: Union[Tuple, List, np.ndarray],
         element: Optional[str] = "nodes",
         method: Optional[str] = "coords",
-        inverse_indices=False,
+        inverse_indices: Union[List[str], Set[str], bool] = False,
         **kwargs,
     ):
         """Subsets an unstructured grid between two latitude and longitude
@@ -68,7 +68,7 @@ def bounding_circle(
         center_coord: Union[Tuple, List, np.ndarray],
         r: Union[float, int],
         element: Optional[str] = "nodes",
-        inverse_indices=False,
+        inverse_indices: Union[List[str], Set[str], bool] = False,
         **kwargs,
     ):
         """Subsets an unstructured grid by returning all elements within some
@@ -86,7 +86,7 @@ def bounding_circle(
             Flag to indicate whether to store the original grids face indices for later use
         """
         grid = self.uxda.uxgrid.subset.bounding_circle(
-            center_coord, r, element, inverse_indices=inverse_indices**kwargs
+            center_coord, r, element, inverse_indices=inverse_indices, **kwargs
         )
         return self.uxda._slice_from_grid(grid)
 
@@ -95,7 +95,7 @@ def nearest_neighbor(
         center_coord: Union[Tuple, List, np.ndarray],
         k: int,
         element: Optional[str] = "nodes",
-        inverse_indices=False,
+        inverse_indices: Union[List[str], Set[str], bool] = False,
         **kwargs,
     ):
         """Subsets an unstructured grid by returning the ``k`` closest
diff --git a/uxarray/subset/grid_accessor.py b/uxarray/subset/grid_accessor.py
index c80686228..2dcb954e2 100644
--- a/uxarray/subset/grid_accessor.py
+++ b/uxarray/subset/grid_accessor.py
@@ -2,7 +2,7 @@
 
 import numpy as np
 
-from typing import TYPE_CHECKING, Union, Tuple, List, Optional
+from typing import TYPE_CHECKING, Union, Tuple, List, Optional, Set
 
 if TYPE_CHECKING:
     from uxarray.grid import Grid
@@ -33,7 +33,7 @@ def bounding_box(
         lat_bounds: Union[Tuple, List, np.ndarray],
         element: Optional[str] = "nodes",
         method: Optional[str] = "coords",
-        inverse_indices=False,
+        inverse_indices: Union[List[str], Set[str], bool] = False,
         **kwargs,
     ):
         """Subsets an unstructured grid between two latitude and longitude
@@ -118,7 +118,7 @@ def bounding_circle(
         center_coord: Union[Tuple, List, np.ndarray],
         r: Union[float, int],
         element: Optional[str] = "nodes",
-        inverse_indices=False,
+        inverse_indices: Union[List[str], Set[str], bool] = False,
         **kwargs,
     ):
         """Subsets an unstructured grid by returning all elements within some
@@ -154,7 +154,7 @@ def nearest_neighbor(
         center_coord: Union[Tuple, List, np.ndarray],
         k: int,
         element: Optional[str] = "nodes",
-        inverse_indices=False,
+        inverse_indices: Union[List[str], Set[str], bool] = False,
         **kwargs,
     ):
         """Subsets an unstructured grid by returning the ``k`` closest

From aaf49ab165af5b72dac0f4b34fba904e68ae8422 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Tue, 7 Jan 2025 09:58:54 -0600
Subject: [PATCH 06/16] updated grid, doc strings, api, test cases

---
 docs/api.rst                                 |  1 +
 test/test_subset.py                          |  6 +++++-
 uxarray/cross_sections/dataarray_accessor.py | 10 ++++++----
 uxarray/cross_sections/grid_accessor.py      | 10 ++++++----
 uxarray/grid/grid.py                         | 16 ++++++++++------
 uxarray/grid/slice.py                        |  5 +++--
 uxarray/subset/dataarray_accessor.py         | 15 +++++++++------
 uxarray/subset/grid_accessor.py              | 15 +++++++++------
 8 files changed, 49 insertions(+), 29 deletions(-)

diff --git a/docs/api.rst b/docs/api.rst
index f9146e69f..10307a16f 100644
--- a/docs/api.rst
+++ b/docs/api.rst
@@ -54,6 +54,7 @@ Indexing
    :toctree: generated/
 
    Grid.isel
+   Grid.inverse_indices
 
 Dimensions
 ~~~~~~~~~~
diff --git a/test/test_subset.py b/test/test_subset.py
index b5fa2fda7..184d0fcb0 100644
--- a/test/test_subset.py
+++ b/test/test_subset.py
@@ -121,7 +121,7 @@ def test_uxda_isel_with_coords():
     assert len(sub.coords['lon_face']) == 3
 
 
-def test_inverse_face_indices():
+def test_inverse_indices():
     grid = ux.open_grid(GRID_PATHS[0])
 
     # Test nearest neighbor subsetting
@@ -145,3 +145,7 @@ def test_inverse_face_indices():
     # Ensure code raises exceptions when the element is edges or nodes
     assert pytest.raises(Exception, grid.subset.bounding_circle, center_coord, r=10, element="edge centers", inverse_indices=True)
     assert pytest.raises(Exception, grid.subset.bounding_circle, center_coord, r=10, element="node centers", inverse_indices=True)
+
+    # Test isel directly
+    subset = grid.isel(n_face=[1], inverse_indices=True)
+    assert subset.inverse_indices is not None
diff --git a/uxarray/cross_sections/dataarray_accessor.py b/uxarray/cross_sections/dataarray_accessor.py
index 48a864a74..fd0e81e84 100644
--- a/uxarray/cross_sections/dataarray_accessor.py
+++ b/uxarray/cross_sections/dataarray_accessor.py
@@ -33,8 +33,9 @@ def constant_latitude(
         lat : float
             The latitude at which to extract the cross-section, in degrees.
             Must be between -90.0 and 90.0
-        inverse_indices : bool, optional
-            If True, stores the original grid indices
+        inverse_indices : Union[List[str], Set[str], bool], optional
+            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
 
         Returns
         -------
@@ -77,8 +78,9 @@ def constant_longitude(
         lon : float
             The latitude at which to extract the cross-section, in degrees.
             Must be between -180.0 and 180.0
-        inverse_indices : bool, optional
-            If True, stores the original grid indices
+        inverse_indices : Union[List[str], Set[str], bool], optional
+            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
 
         Returns
         -------
diff --git a/uxarray/cross_sections/grid_accessor.py b/uxarray/cross_sections/grid_accessor.py
index 36b91521a..17fee3f8e 100644
--- a/uxarray/cross_sections/grid_accessor.py
+++ b/uxarray/cross_sections/grid_accessor.py
@@ -37,8 +37,9 @@ def constant_latitude(
             Must be between -90.0 and 90.0
         return_face_indices : bool, optional
             If True, also returns the indices of the faces that intersect with the line of constant latitude.
-        inverse_indices : bool, optional
-            If True, stores the original grid indices
+        inverse_indices : Union[List[str], Set[str], bool], optional
+            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
 
         Returns
         -------
@@ -94,8 +95,9 @@ def constant_longitude(
             Must be between -90.0 and 90.0
         return_face_indices : bool, optional
             If True, also returns the indices of the faces that intersect with the line of constant longitude.
-        inverse_indices : bool, optional
-            If True, stores the original grid indices
+        inverse_indices : Union[List[str], Set[str], bool], optional
+            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
 
         Returns
         -------
diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index 51a11f94e..03a54b191 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -139,6 +139,12 @@ class Grid:
     source_dims_dict : dict, default={}
         Mapping of dimensions from the source dataset to their UGRID equivalent (i.e. {nCell : n_face})
 
+    is_subset : bool, default=False
+        Flag to mark if the grid is a subset or not
+
+    inverse_indices: xr.Dataset, defaul=None
+        A dataset of indices that correspond to the original grid, if the grid being constructed is a subset
+
     Examples
     ----------
 
@@ -198,7 +204,7 @@ def __init__(
         self.is_subset = is_subset
 
         if inverse_indices is not None:
-            self.inverse_indices = inverse_indices
+            self._inverse_indices = inverse_indices
 
         # cached parameters for GeoDataFrame conversions
         self._gdf_cached_parameters = {
@@ -1532,11 +1538,6 @@ def inverse_indices(self):
                 "Grid is not a subset, therefore no inverse face indices exist"
             )
 
-    @inverse_indices.setter
-    def inverse_indices(self, value):
-        assert isinstance(value, xr.Dataset)
-        self._inverse_indices = value
-
     def chunk(self, n_node="auto", n_edge="auto", n_face="auto"):
         """Converts all arrays to dask arrays with given chunks across grid
         dimensions in-place.
@@ -2244,6 +2245,9 @@ def isel(
         exclusive and clipped indexing is in the works.
 
         Parameters
+        inverse_indices : Union[List[str], Set[str], bool], default=False
+            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
         **dims_kwargs: kwargs
             Dimension to index, one of ['n_node', 'n_edge', 'n_face']
 
diff --git a/uxarray/grid/slice.py b/uxarray/grid/slice.py
index 3f7416d84..9045e0be7 100644
--- a/uxarray/grid/slice.py
+++ b/uxarray/grid/slice.py
@@ -14,7 +14,6 @@ def _slice_node_indices(
     grid,
     indices,
     inclusive=True,
-    inverse_indices: Union[List[str], Set[str], bool] = False,
 ):
     """Slices (indexes) an unstructured grid given a list/array of node
     indices, returning a new Grid composed of elements that contain the nodes
@@ -45,7 +44,6 @@ def _slice_edge_indices(
     grid,
     indices,
     inclusive=True,
-    inverse_indices: Union[List[str], Set[str], bool] = False,
 ):
     """Slices (indexes) an unstructured grid given a list/array of edge
     indices, returning a new Grid composed of elements that contain the edges
@@ -91,6 +89,9 @@ def _slice_face_indices(
     inclusive: bool
         Whether to perform inclusive (i.e. elements must contain at least one desired feature from a slice) as opposed
         to exclusive (i.e elements be made up all desired features from a slice)
+    inverse_indices : Union[List[str], Set[str], bool], optional
+        Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+        other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
     """
     if inclusive is False:
         raise ValueError("Exclusive slicing is not yet supported.")
diff --git a/uxarray/subset/dataarray_accessor.py b/uxarray/subset/dataarray_accessor.py
index b71e78f08..23609ba65 100644
--- a/uxarray/subset/dataarray_accessor.py
+++ b/uxarray/subset/dataarray_accessor.py
@@ -54,8 +54,9 @@ def bounding_box(
             face centers, or edge centers lie within the bounds.
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
-        inverse_indices : bool
-            Flag to indicate whether to store the original grids face indices for later use
+        inverse_indices : Union[List[str], Set[str], bool], optional
+            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
         """
         grid = self.uxda.uxgrid.subset.bounding_box(
             lon_bounds, lat_bounds, element, method, inverse_indices=inverse_indices
@@ -82,8 +83,9 @@ def bounding_circle(
             Radius of bounding circle (in degrees)
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
-        inverse_indices : bool
-            Flag to indicate whether to store the original grids face indices for later use
+        inverse_indices : Union[List[str], Set[str], bool], optional
+            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
         """
         grid = self.uxda.uxgrid.subset.bounding_circle(
             center_coord, r, element, inverse_indices=inverse_indices, **kwargs
@@ -109,8 +111,9 @@ def nearest_neighbor(
             Number of neighbors to query
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
-        inverse_indices : bool
-            Flag to indicate whether to store the original grids face indices for later use
+        inverse_indices : Union[List[str], Set[str], bool], optional
+            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
         """
 
         grid = self.uxda.uxgrid.subset.nearest_neighbor(
diff --git a/uxarray/subset/grid_accessor.py b/uxarray/subset/grid_accessor.py
index 2dcb954e2..d0d8a9d08 100644
--- a/uxarray/subset/grid_accessor.py
+++ b/uxarray/subset/grid_accessor.py
@@ -54,8 +54,9 @@ def bounding_box(
             face centers, or edge centers lie within the bounds.
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
-        inverse_indices : bool
-            Flag to indicate whether to store the original grids face indices for later use
+        inverse_indices : Union[List[str], Set[str], bool], optional
+            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
         """
 
         if method == "coords":
@@ -132,8 +133,9 @@ def bounding_circle(
             Radius of bounding circle (in degrees)
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
-        inverse_indices : bool
-            Flag to indicate whether to store the original grids face indices for later use
+        inverse_indices : Union[List[str], Set[str], bool], optional
+            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
         """
 
         coords = np.asarray(center_coord)
@@ -168,8 +170,9 @@ def nearest_neighbor(
             Number of neighbors to query
         element: str
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
-        inverse_indices : bool
-            Flag to indicate whether to store the original grids face indices for later use
+        inverse_indices : Union[List[str], Set[str], bool], optional
+            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
+            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
         """
 
         coords = np.asarray(center_coord)

From 00973c72523f712a9d796c741fcc4804441d6370 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Tue, 7 Jan 2025 10:00:05 -0600
Subject: [PATCH 07/16] fixed leftover variables

---
 uxarray/grid/slice.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/uxarray/grid/slice.py b/uxarray/grid/slice.py
index 9045e0be7..1bfc8a017 100644
--- a/uxarray/grid/slice.py
+++ b/uxarray/grid/slice.py
@@ -37,7 +37,7 @@ def _slice_node_indices(
     face_indices = np.unique(grid.node_face_connectivity.values[indices].ravel())
     face_indices = face_indices[face_indices != INT_FILL_VALUE]
 
-    return _slice_face_indices(grid, face_indices, inverse_indices=inverse_indices)
+    return _slice_face_indices(grid, face_indices)
 
 
 def _slice_edge_indices(
@@ -67,7 +67,7 @@ def _slice_edge_indices(
     face_indices = np.unique(grid.edge_face_connectivity.values[indices].ravel())
     face_indices = face_indices[face_indices != INT_FILL_VALUE]
 
-    return _slice_face_indices(grid, face_indices, inverse_indices=inverse_indices)
+    return _slice_face_indices(grid, face_indices)
 
 
 def _slice_face_indices(

From f226da0445c482e3b83108e655ac46981e09fc9e Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Tue, 7 Jan 2025 13:53:49 -0600
Subject: [PATCH 08/16] Fixed failing tests

---
 uxarray/grid/grid.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index 03a54b191..5c71f9d42 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -2268,7 +2268,7 @@ def isel(
                     "Inverse indices are not yet supported for node selection, please use face centers"
                 )
             return _slice_node_indices(
-                self, dim_kwargs["n_node"], inverse_indices=inverse_indices
+                self, dim_kwargs["n_node"]
             )
 
         elif "n_edge" in dim_kwargs:
@@ -2277,7 +2277,7 @@ def isel(
                     "Inverse indices are not yet supported for edge selection, please use face centers"
                 )
             return _slice_edge_indices(
-                self, dim_kwargs["n_edge"], inverse_indices=inverse_indices
+                self, dim_kwargs["n_edge"]
             )
 
         elif "n_face" in dim_kwargs:

From 1e52e02bdada8e4431210c2d0ba3b413703e5397 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Tue, 7 Jan 2025 13:56:48 -0600
Subject: [PATCH 09/16] Update grid.py

---
 uxarray/grid/grid.py | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index 5c71f9d42..9f62da303 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -2267,18 +2267,14 @@ def isel(
                 raise Exception(
                     "Inverse indices are not yet supported for node selection, please use face centers"
                 )
-            return _slice_node_indices(
-                self, dim_kwargs["n_node"]
-            )
+            return _slice_node_indices(self, dim_kwargs["n_node"])
 
         elif "n_edge" in dim_kwargs:
             if inverse_indices:
                 raise Exception(
                     "Inverse indices are not yet supported for edge selection, please use face centers"
                 )
-            return _slice_edge_indices(
-                self, dim_kwargs["n_edge"]
-            )
+            return _slice_edge_indices(self, dim_kwargs["n_edge"])
 
         elif "n_face" in dim_kwargs:
             return _slice_face_indices(

From 129f9c52c30658b81c35fdc13450272377300215 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Wed, 8 Jan 2025 10:18:32 -0600
Subject: [PATCH 10/16] New naming convention, fixed spelling errors

---
 test/test_subset.py                          |  2 +-
 uxarray/cross_sections/dataarray_accessor.py |  4 ++--
 uxarray/cross_sections/grid_accessor.py      |  4 ++--
 uxarray/grid/grid.py                         | 10 +++++-----
 uxarray/grid/slice.py                        | 10 +++++-----
 uxarray/subset/dataarray_accessor.py         |  6 +++---
 uxarray/subset/grid_accessor.py              |  6 +++---
 7 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/test/test_subset.py b/test/test_subset.py
index 184d0fcb0..db2108971 100644
--- a/test/test_subset.py
+++ b/test/test_subset.py
@@ -144,7 +144,7 @@ def test_inverse_indices():
 
     # Ensure code raises exceptions when the element is edges or nodes
     assert pytest.raises(Exception, grid.subset.bounding_circle, center_coord, r=10, element="edge centers", inverse_indices=True)
-    assert pytest.raises(Exception, grid.subset.bounding_circle, center_coord, r=10, element="node centers", inverse_indices=True)
+    assert pytest.raises(Exception, grid.subset.bounding_circle, center_coord, r=10, element="nodes", inverse_indices=True)
 
     # Test isel directly
     subset = grid.isel(n_face=[1], inverse_indices=True)
diff --git a/uxarray/cross_sections/dataarray_accessor.py b/uxarray/cross_sections/dataarray_accessor.py
index fd0e81e84..52599c7a4 100644
--- a/uxarray/cross_sections/dataarray_accessor.py
+++ b/uxarray/cross_sections/dataarray_accessor.py
@@ -35,7 +35,7 @@ def constant_latitude(
             Must be between -90.0 and 90.0
         inverse_indices : Union[List[str], Set[str], bool], optional
             Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+            other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
 
         Returns
         -------
@@ -80,7 +80,7 @@ def constant_longitude(
             Must be between -180.0 and 180.0
         inverse_indices : Union[List[str], Set[str], bool], optional
             Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+            other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
 
         Returns
         -------
diff --git a/uxarray/cross_sections/grid_accessor.py b/uxarray/cross_sections/grid_accessor.py
index 17fee3f8e..76485fbda 100644
--- a/uxarray/cross_sections/grid_accessor.py
+++ b/uxarray/cross_sections/grid_accessor.py
@@ -39,7 +39,7 @@ def constant_latitude(
             If True, also returns the indices of the faces that intersect with the line of constant latitude.
         inverse_indices : Union[List[str], Set[str], bool], optional
             Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+            other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
 
         Returns
         -------
@@ -97,7 +97,7 @@ def constant_longitude(
             If True, also returns the indices of the faces that intersect with the line of constant longitude.
         inverse_indices : Union[List[str], Set[str], bool], optional
             Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+            other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
 
         Returns
         -------
diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index 9f62da303..bf7f8864f 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -142,7 +142,7 @@ class Grid:
     is_subset : bool, default=False
         Flag to mark if the grid is a subset or not
 
-    inverse_indices: xr.Dataset, defaul=None
+    inverse_indices: xr.Dataset, default=None
         A dataset of indices that correspond to the original grid, if the grid being constructed is a subset
 
     Examples
@@ -168,7 +168,7 @@ def __init__(
         grid_ds: xr.Dataset,
         source_grid_spec: Optional[str] = None,
         source_dims_dict: Optional[dict] = {},
-        is_subset=False,
+        is_subset: bool = False,
         inverse_indices: Optional[xr.Dataset] = None,
     ):
         # check if inputted dataset is a minimum representable 2D UGRID unstructured grid
@@ -1529,7 +1529,7 @@ def global_sphere_coverage(self):
         return not self.partial_sphere_coverage
 
     @property
-    def inverse_indices(self):
+    def inverse_indices(self) -> xr.Dataset:
         """Indices for a subset that map each face in the subset back to the original grid"""
         if self.is_subset:
             return self._inverse_indices
@@ -2246,8 +2246,8 @@ def isel(
 
         Parameters
         inverse_indices : Union[List[str], Set[str], bool], default=False
-            Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+            Indicates whether to store the original grids indices. Passing `True` stores the original face indices,
+            other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
         **dims_kwargs: kwargs
             Dimension to index, one of ['n_node', 'n_edge', 'n_face']
 
diff --git a/uxarray/grid/slice.py b/uxarray/grid/slice.py
index 1bfc8a017..a85c9f78f 100644
--- a/uxarray/grid/slice.py
+++ b/uxarray/grid/slice.py
@@ -91,7 +91,7 @@ def _slice_face_indices(
         to exclusive (i.e elements be made up all desired features from a slice)
     inverse_indices : Union[List[str], Set[str], bool], optional
         Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-        other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+        other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
     """
     if inclusive is False:
         raise ValueError("Exclusive slicing is not yet supported.")
@@ -151,12 +151,12 @@ def _slice_face_indices(
         inverse_indices_ds = xr.Dataset()
 
         index_types = {
-            "face centers": face_indices,
-            "edge centers": edge_indices,
-            "nodes": node_indices,
+            "face": face_indices,
+            "edge": edge_indices,
+            "node": node_indices,
         }
         if isinstance(inverse_indices, bool):
-            inverse_indices_ds["face centers"] = face_indices
+            inverse_indices_ds["face"] = face_indices
         else:
             for index_type in inverse_indices[0]:
                 if index_type in index_types:
diff --git a/uxarray/subset/dataarray_accessor.py b/uxarray/subset/dataarray_accessor.py
index 23609ba65..2d966c587 100644
--- a/uxarray/subset/dataarray_accessor.py
+++ b/uxarray/subset/dataarray_accessor.py
@@ -56,7 +56,7 @@ def bounding_box(
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
         inverse_indices : Union[List[str], Set[str], bool], optional
             Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+            other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
         """
         grid = self.uxda.uxgrid.subset.bounding_box(
             lon_bounds, lat_bounds, element, method, inverse_indices=inverse_indices
@@ -85,7 +85,7 @@ def bounding_circle(
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
         inverse_indices : Union[List[str], Set[str], bool], optional
             Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+            other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
         """
         grid = self.uxda.uxgrid.subset.bounding_circle(
             center_coord, r, element, inverse_indices=inverse_indices, **kwargs
@@ -113,7 +113,7 @@ def nearest_neighbor(
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
         inverse_indices : Union[List[str], Set[str], bool], optional
             Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+            other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
         """
 
         grid = self.uxda.uxgrid.subset.nearest_neighbor(
diff --git a/uxarray/subset/grid_accessor.py b/uxarray/subset/grid_accessor.py
index d0d8a9d08..a504179f1 100644
--- a/uxarray/subset/grid_accessor.py
+++ b/uxarray/subset/grid_accessor.py
@@ -56,7 +56,7 @@ def bounding_box(
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
         inverse_indices : Union[List[str], Set[str], bool], optional
             Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+            other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
         """
 
         if method == "coords":
@@ -135,7 +135,7 @@ def bounding_circle(
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
         inverse_indices : Union[List[str], Set[str], bool], optional
             Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+            other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
         """
 
         coords = np.asarray(center_coord)
@@ -172,7 +172,7 @@ def nearest_neighbor(
             Element for use with `coords` comparison, one of `nodes`, `face centers`, or `edge centers`
         inverse_indices : Union[List[str], Set[str], bool], optional
             Indicates whether to store the original grids indices. Passing `True` stores the original face centers,
-            other reverse indices can be stored by passing any or all of the following: (["face centers", "edge centers", "nodes"], True)
+            other reverse indices can be stored by passing any or all of the following: (["face", "edge", "node"], True)
         """
 
         coords = np.asarray(center_coord)

From 23a2b9a916e9f0a46533d14568489819b1636d86 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Wed, 8 Jan 2025 13:32:48 -0600
Subject: [PATCH 11/16] Updated subsetting notebook

---
 docs/user-guide/subset.ipynb | 95 +++++++++++++++++++++++++++++++++++-
 test/test_subset.py          |  3 +-
 uxarray/grid/slice.py        |  3 ++
 3 files changed, 99 insertions(+), 2 deletions(-)

diff --git a/docs/user-guide/subset.ipynb b/docs/user-guide/subset.ipynb
index 07df1e82b..368c34d5e 100644
--- a/docs/user-guide/subset.ipynb
+++ b/docs/user-guide/subset.ipynb
@@ -131,6 +131,7 @@
    "cell_type": "markdown",
    "metadata": {
     "collapsed": false,
+    "jp-MarkdownHeadingCollapsed": true,
     "jupyter": {
      "outputs_hidden": false
     }
@@ -553,6 +554,98 @@
     "print(\"Bounding Box Mean:      \", bbox_subset_nodes.values.mean())\n",
     "print(\"Bounding Circle Mean:   \", bcircle_subset.values.mean())"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Retrieving Orignal Grid Indices"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Sometimes having the original grids' indices is useful. These indices can be stored within the subset with the `inverse_indices` variable. This can be used to store the indices of the original face centers, edge centers, and node indices. This variable can be used within the subset as follows:\n",
+    "\n",
+    "* Passing in `True`, which will store the face center indices\n",
+    "* Passing in a list of which indices to store, along with `True`, to indicate what kind of original grid indices to store.\n",
+    "    * Options for which indices to select include: `face`, `node`, and `edge`\n",
+    "\n",
+    "This currently only works when the element is `face centers`. Elements `nodes` and `edge centers` will be supported in the future."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "subset_indices = uxds[\"relhum_200hPa\"][0].subset.bounding_circle(center_coord, r, element=\"face centers\", \n",
+    "                                                                 inverse_indices=(['face', 'node', 'edge'], True))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "These indices can be retrieve through the grid:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "subset_indices.uxgrid.inverse_indices"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Determining if a Grid is a Subset"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "To check if a Grid (or dataset using `.uxgrid`) is a subset, we can use `Grid.is_subset`, which will return either `True` or `False`, depending on whether the `Grid` is a subset. Since `subset_indices` is a subset, using this feature we will return `True`:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "subset_indices.uxgrid.is_subset"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The file we have been using to create these subsets, `uxds`, is not a subset, so using the same call we will return `False:`"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "uxds.uxgrid.is_subset"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
   }
  ],
  "metadata": {
@@ -571,7 +664,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.11.9"
+   "version": "3.12.7"
   }
  },
  "nbformat": 4,
diff --git a/test/test_subset.py b/test/test_subset.py
index db2108971..0809320b8 100644
--- a/test/test_subset.py
+++ b/test/test_subset.py
@@ -142,9 +142,10 @@ def test_inverse_indices():
 
     assert subset.inverse_indices is not None
 
-    # Ensure code raises exceptions when the element is edges or nodes
+    # Ensure code raises exceptions when the element is edges or nodes or inverse_indices is incorrect
     assert pytest.raises(Exception, grid.subset.bounding_circle, center_coord, r=10, element="edge centers", inverse_indices=True)
     assert pytest.raises(Exception, grid.subset.bounding_circle, center_coord, r=10, element="nodes", inverse_indices=True)
+    assert pytest.raises(ValueError, grid.subset.bounding_circle, center_coord, r=10, element="face center", inverse_indices=(['not right'], True))
 
     # Test isel directly
     subset = grid.isel(n_face=[1], inverse_indices=True)
diff --git a/uxarray/grid/slice.py b/uxarray/grid/slice.py
index a85c9f78f..66e1bbbfc 100644
--- a/uxarray/grid/slice.py
+++ b/uxarray/grid/slice.py
@@ -161,6 +161,9 @@ def _slice_face_indices(
             for index_type in inverse_indices[0]:
                 if index_type in index_types:
                     inverse_indices_ds[index_type] = index_types[index_type]
+                else:
+                    raise ValueError("Incorrect type of index for `inverse_indices`. Try passing one of the following "
+                                     "instead: 'face', 'edge', 'node'")
 
         return Grid.from_dataset(
             ds,

From 1a45876a33f11c5089fb9230be79a7e1e34a0c95 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Wed, 8 Jan 2025 13:33:57 -0600
Subject: [PATCH 12/16] Fixed precommit

---
 docs/user-guide/subset.ipynb | 8 ++++++--
 uxarray/grid/slice.py        | 6 ++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/docs/user-guide/subset.ipynb b/docs/user-guide/subset.ipynb
index 368c34d5e..8110e98cb 100644
--- a/docs/user-guide/subset.ipynb
+++ b/docs/user-guide/subset.ipynb
@@ -581,8 +581,12 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "subset_indices = uxds[\"relhum_200hPa\"][0].subset.bounding_circle(center_coord, r, element=\"face centers\", \n",
-    "                                                                 inverse_indices=(['face', 'node', 'edge'], True))"
+    "subset_indices = uxds[\"relhum_200hPa\"][0].subset.bounding_circle(\n",
+    "    center_coord,\n",
+    "    r,\n",
+    "    element=\"face centers\",\n",
+    "    inverse_indices=([\"face\", \"node\", \"edge\"], True),\n",
+    ")"
    ]
   },
   {
diff --git a/uxarray/grid/slice.py b/uxarray/grid/slice.py
index 66e1bbbfc..94e8e0eb8 100644
--- a/uxarray/grid/slice.py
+++ b/uxarray/grid/slice.py
@@ -162,8 +162,10 @@ def _slice_face_indices(
                 if index_type in index_types:
                     inverse_indices_ds[index_type] = index_types[index_type]
                 else:
-                    raise ValueError("Incorrect type of index for `inverse_indices`. Try passing one of the following "
-                                     "instead: 'face', 'edge', 'node'")
+                    raise ValueError(
+                        "Incorrect type of index for `inverse_indices`. Try passing one of the following "
+                        "instead: 'face', 'edge', 'node'"
+                    )
 
         return Grid.from_dataset(
             ds,

From 434b3899c1aa35ce45ecba08056311c99f2fe776 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Thu, 9 Jan 2025 12:44:53 -0600
Subject: [PATCH 13/16] Added is_subset property

---
 docs/user-guide/subset.ipynb | 8 --------
 uxarray/grid/grid.py         | 6 +++++-
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/docs/user-guide/subset.ipynb b/docs/user-guide/subset.ipynb
index 8110e98cb..c1e7a97df 100644
--- a/docs/user-guide/subset.ipynb
+++ b/docs/user-guide/subset.ipynb
@@ -131,7 +131,6 @@
    "cell_type": "markdown",
    "metadata": {
     "collapsed": false,
-    "jp-MarkdownHeadingCollapsed": true,
     "jupyter": {
      "outputs_hidden": false
     }
@@ -643,13 +642,6 @@
    "source": [
     "uxds.uxgrid.is_subset"
    ]
-  },
-  {
-   "cell_type": "code",
-   "execution_count": null,
-   "metadata": {},
-   "outputs": [],
-   "source": []
   }
  ],
  "metadata": {
diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index bf7f8864f..7acd6c6f3 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -201,7 +201,7 @@ def __init__(
         # initialize attributes
         self._antimeridian_face_indices = None
         self._ds.assign_attrs({"source_grid_spec": self.source_grid_spec})
-        self.is_subset = is_subset
+        self._is_subset = is_subset
 
         if inverse_indices is not None:
             self._inverse_indices = inverse_indices
@@ -1538,6 +1538,10 @@ def inverse_indices(self) -> xr.Dataset:
                 "Grid is not a subset, therefore no inverse face indices exist"
             )
 
+    @property
+    def is_subset(self):
+        return self._is_subset
+
     def chunk(self, n_node="auto", n_edge="auto", n_face="auto"):
         """Converts all arrays to dask arrays with given chunks across grid
         dimensions in-place.

From 702736b3981c58e842e102cbc7f7db401ea9b9c2 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <95507181+aaronzedwick@users.noreply.github.com>
Date: Thu, 9 Jan 2025 13:04:42 -0600
Subject: [PATCH 14/16] Update uxarray/grid/grid.py

Co-authored-by: Philip Chmielowiec <67855069+philipc2@users.noreply.github.com>
---
 uxarray/grid/grid.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index 7acd6c6f3..3f1611713 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -1539,7 +1539,7 @@ def inverse_indices(self) -> xr.Dataset:
             )
 
     @property
-    def is_subset(self):
+    def is_subset(self) -> bool:
         return self._is_subset
 
     def chunk(self, n_node="auto", n_edge="auto", n_face="auto"):

From 4ea26e430c4a1a36327118563bd54b772ede60fe Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Thu, 9 Jan 2025 13:15:07 -0600
Subject: [PATCH 15/16] Added doc string, updated test case

---
 test/test_subset.py  | 2 +-
 uxarray/grid/grid.py | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/test/test_subset.py b/test/test_subset.py
index 0809320b8..f13ae4919 100644
--- a/test/test_subset.py
+++ b/test/test_subset.py
@@ -149,4 +149,4 @@ def test_inverse_indices():
 
     # Test isel directly
     subset = grid.isel(n_face=[1], inverse_indices=True)
-    assert subset.inverse_indices is not None
+    assert subset.inverse_indices.face.values == 1
diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index 7acd6c6f3..8bf752b34 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -1540,6 +1540,7 @@ def inverse_indices(self) -> xr.Dataset:
 
     @property
     def is_subset(self):
+        """Returns `True` if the Grid is a subset, and 'False' otherwise."""
         return self._is_subset
 
     def chunk(self, n_node="auto", n_edge="auto", n_face="auto"):

From a97870652169094c3b4627d01372545a37593c32 Mon Sep 17 00:00:00 2001
From: Aaron Zedwick <aazedwick@gmail.com>
Date: Thu, 9 Jan 2025 13:19:27 -0600
Subject: [PATCH 16/16] Update grid.py

---
 uxarray/grid/grid.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/uxarray/grid/grid.py b/uxarray/grid/grid.py
index 8bf752b34..c975ebff8 100644
--- a/uxarray/grid/grid.py
+++ b/uxarray/grid/grid.py
@@ -1540,7 +1540,7 @@ def inverse_indices(self) -> xr.Dataset:
 
     @property
     def is_subset(self):
-        """Returns `True` if the Grid is a subset, and 'False' otherwise."""
+        """Returns `True` if the Grid is a subset, 'False' otherwise."""
         return self._is_subset
 
     def chunk(self, n_node="auto", n_edge="auto", n_face="auto"):