docs: add docstrings

docs/graphs/node_coordinates.rst

@@ -25,6 +25,8 @@ a file:
    node_coordinates/zarr_dataset
    node_coordinates/npz_file
    node_coordinates/icon_mesh
+   node_coordinates/text_file
+   node_coordinates/latlon_arrays
 
 or based on other algorithms. A commonn approach is to use an
 icosahedron to project the earth's surface, and refine it iteratively to

docs/graphs/node_coordinates/latlon_arrays.rst

@@ -0,0 +1,18 @@
+#######################################
+ From latitude & longitude coordinates
+#######################################
+
+Nodes can also be created directly using latitude and longitude
+coordinates. Below is an example demonstrating how to add these nodes to
+a graph:
+
+.. code:: python
+
+   from anemoi.graphs.nodes import LatLonNodes
+
+   ...
+
+   lats = np.array([45.0, 45.0, 40.0, 40.0])
+   lons = np.array([5.0, 10.0, 10.0, 5.0])
+
+   graph = LatLonNodes(latitudes=lats, longitudes=lons, name="my_nodes").update_graph(graph)

docs/graphs/node_coordinates/text_file.rst

@@ -0,0 +1,20 @@
+################
+ From .TXT file
+################
+
+To define the `node coordinates` based on a TXT file, you can configure
+the YAML as follows:
+
+.. code:: yaml
+
+   nodes:
+     data: # name of the nodes
+       node_builder:
+         _target_: anemoi.graphs.nodes.TextNodes
+         dataset: my_file.txt
+         idx_lon: 0
+         idx_lat: 1
+
+Here, dataset refers to the path of the TXT file that contains the
+latitude and longitude values in the columns specified by `idx_lat` and
+`idx_lon`, respectively.

src/anemoi/graphs/nodes/builders/from_data.py

@@ -24,10 +24,10 @@ class LatLonNodes(BaseNodeBuilder):
 
     Attributes
     ----------
-    latitudes : np.ndarray
-        The latitude of the nodes.
-    longitudes : np.ndarray
-        The longitude of the nodes.
+    latitudes : list | np.ndarray
+        The latitude of the nodes, in degrees.
+    longitudes : list | np.ndarray
+        The longitude of the nodes, in degrees.
 
     Methods
     -------
@@ -41,8 +41,11 @@ class LatLonNodes(BaseNodeBuilder):
         Update the graph with new nodes and attributes.
     """
 
-    def __init__(self, latitudes: np.ndarray, longitudes: np.ndarray, name: str) -> None:
+    def __init__(self, latitudes: list[float] | np.ndarray, longitudes: list[float] | np.ndarray, name: str) -> None:
         super().__init__(name)
+        self.latitudes = latitudes if isinstance(latitudes, np.ndarray) else np.array(latitudes)
+        self.longitudes = longitudes if isinstance(longitudes, np.ndarray) else np.array(longitudes)
+
         assert len(self.latitudes) == len(
             self.longitudes
         ), f"Lenght of latitudes and longitudes must match but {len(self.latitudes)}!={len(self.longitudes)}."
@@ -52,8 +55,6 @@ def __init__(self, latitudes: np.ndarray, longitudes: np.ndarray, name: str) ->
         assert self.longitudes.ndim == 1 or (
             self.longitudes.ndim == 2 and self.longitudes.shape[1] == 1
         ), "longitudes must have shape (N, ) or (N, 1)."
-        self.latitudes = latitudes
-        self.longitudes = longitudes
 
     def get_coordinates(self) -> torch.Tensor:
         """Get the coordinates of the nodes.