Add additional variable check to SCRIP reader (#1233)

* o Fix SCRIP reader to use grid_rank, bug found while reading a SCRIP grid provided in ESMPy ll1deg_grid.nc

* o Use imask instead of rank as our test cases have grids that don't have grid_rank

* o Add multiple options for checking SCRIP

* o Fix formatting

* o Use any construct for better performance and redability

Author: rajeeja

uxarray/io/_scrip.py

@@ -15,7 +15,8 @@ def _to_ugrid(in_ds, out_ds):
 
     source_dims_dict = {}
 
-    if in_ds["grid_area"].all():
+    # Check if any of imask, area or rank are present
+    if any(key in in_ds for key in ["grid_imask", "grid_rank", "grid_area"]):
         # Create node_lon & node_lat variables from grid_corner_lat/lon
         # Turn latitude and longitude scrip arrays into 1D
         corner_lat = in_ds["grid_corner_lat"].values.ravel()
@@ -131,7 +132,7 @@ def _encode_scrip(face_node_connectivity, node_lon, node_lat, face_areas):
     Currently, supports creating unstructured SCRIP grid files following traditional
     SCRIP naming practices (grid_corner_lat, grid_center_lat, etc).
 
-    Unstructured grid SCRIP files will have ``grid_rank=1`` and include variables
+    Unstructured grid SCRIP files typically have ``grid_rank=1`` and include variables
     ``grid_imask`` and ``grid_area`` in the dataset.
 
     More information on structured vs unstructured SCRIP files can be found here on the `Earth System Modeling Framework <https://earthsystemmodeling.org/docs/release/ESMF_6_2_0/ESMF_refdoc/node3.html>`_ website.