Move all iris.mesh.save into iris.fileformats.netcdf.save

Fix experimental.ugrid import of save_mesh

lib/iris/experimental/ugrid.py

@@ -30,11 +30,11 @@
 import threading
 
 from .._deprecation import warn_deprecated
+from ..mesh import save_mesh
 from ..mesh.load import load_mesh, load_meshes
 from ..mesh.mesh import Connectivity as _Connectivity
 from ..mesh.mesh import Mesh as _Mesh
 from ..mesh.mesh import MeshCoord as _MeshCoord
-from ..mesh.save import save_mesh
 from ..mesh.utils import recombine_submeshes
 
 

lib/iris/fileformats/netcdf/saver.py

@@ -2796,3 +2796,42 @@ def is_valid_packspec(p):
         result = sman.delayed_completion()
 
     return result
+
+
+def save_mesh(mesh, filename, netcdf_format="NETCDF4"):
+    """Save mesh(es) to a netCDF file.
+
+    Parameters
+    ----------
+    mesh : :class:`iris.mesh.MeshXY` or iterable
+        Mesh(es) to save.
+    filename : str
+        Name of the netCDF file to create.
+    netcdf_format : str, default="NETCDF4"
+        Underlying netCDF file format, one of 'NETCDF4', 'NETCDF4_CLASSIC',
+        'NETCDF3_CLASSIC' or 'NETCDF3_64BIT'. Default is 'NETCDF4' format.
+
+    """
+    # TODO: integrate with standard saving API when no longer 'experimental'.
+
+    if isinstance(mesh, typing.Iterable):
+        meshes = mesh
+    else:
+        meshes = [mesh]
+
+    # Initialise Manager for saving
+    with Saver(filename, netcdf_format) as sman:
+        # Iterate through the list.
+        for mesh in meshes:
+            # Get suitable dimension names.
+            mesh_dimensions, _ = sman._get_dim_names(mesh)
+
+            # Create dimensions.
+            sman._create_cf_dimensions(cube=None, dimension_names=mesh_dimensions)
+
+            # Create the mesh components.
+            sman._add_mesh(mesh)
+
+        # Add a conventions attribute.
+        # TODO: add 'UGRID' to conventions, when this is agreed with CF ?
+        sman.update_global_attributes(Conventions=CF_CONVENTIONS_VERSION)

lib/iris/mesh/__init__.py

@@ -8,10 +8,11 @@
 Based on CF UGRID Conventions (v1.0), https://ugrid-conventions.github.io/ugrid-conventions/.
 """
 
+from iris.fileformats.netcdf.saver import save_mesh
+
 from ..config import get_logger
 from .load import load_mesh, load_meshes
 from .mesh import Connectivity, MeshCoord, MeshXY
-from .save import save_mesh
 from .utils import recombine_submeshes
 
 __all__ = [

lib/iris/tests/unit/fileformats/netcdf/saver/test_Saver__ugrid.py

@@ -23,8 +23,7 @@
 from iris.coords import AuxCoord
 from iris.cube import Cube, CubeList
 from iris.fileformats.netcdf import _thread_safe_nc
-from iris.mesh.mesh import Connectivity, MeshXY
-from iris.mesh.save import save_mesh
+from iris.mesh import Connectivity, MeshXY, save_mesh
 from iris.tests.stock import realistic_4d
 
 XY_LOCS = ("x", "y")