removed grid variable and attrs from delft3d4 uds (#844)

* removed grid variable and attrs from delft3d4 uds

* added d3d testcase

* updated whatsnew

dfm_tools/xugrid_helpers.py

@@ -435,9 +435,25 @@ def open_dataset_delft3d4(file_nc, **kwargs):
     ds_stacked = ds_stacked.drop_vars(['M','N','mesh2d_nFaces'])
     uds = xu.UgridDataset(ds_stacked,grids=[grid]) 
 
-    uds = uds.drop_vars(['XCOR','YCOR'])
+    uds = uds.drop_vars(['XCOR','YCOR','grid'])
     uds = uds.drop_dims(['MC','NC']) #clean up dataset by dropping corner dims (drops also variabes with U/V masks and U/V/C bedlevel)
 
+    # convert to xarray.Dataset to update/remove attrs
+    ds_temp = uds.ugrid.to_dataset()
+
+    # set vertical dimensions attr
+    # TODO: would be more convenient to do within xu.Ugrid2d(): https://github.com/Deltares/xugrid/issues/195#issuecomment-2111841390
+    grid_attrs = {"vertical_dimensions": ds.grid.attrs["vertical_dimensions"]}
+    ds_temp["mesh2d"] = ds_temp["mesh2d"].assign_attrs(grid_attrs)
+
+    # drop attrs pointing to the removed grid variable (topology is now in mesh2d)
+    # TODO: this is not possible on the xu.UgridDataset directly
+    for varn in ds_temp.data_vars:
+        if "grid" in ds_temp[varn].attrs.keys():
+            del ds_temp[varn].attrs["grid"]
+
+    uds = xu.UgridDataset(ds_temp)
+
     return uds
 
 

docs/whats-new.md

@@ -6,6 +6,7 @@
 ### Fix
 - improved `dfmt.download.copernicusmarine_reset()` by changing order of tasks in [#833](https://github.com/Deltares/dfm_tools/pull/833)
 - improved performance of `dfmt.merge_meteofiles()` by using more generic chunking method in [#840](https://github.com/Deltares/dfm_tools/pull/840)
+- improved `dfmt.open_dataset_delft3d4()` by dropping original `grid` variable and attrs in [#844](https://github.com/Deltares/dfm_tools/pull/844)
 
 
 ## 0.22.0 (2024-04-09)

tests/test_xugrid_helpers.py

@@ -189,3 +189,17 @@ def test_enrich_rst_with_map():
 
     uda_rst = uds_rst['DetCS1']
     assert "mesh2d_face_x" in uda_rst.coords
+
+
+@pytest.mark.unittest
+def test_open_dataset_delft3d4():
+    file_nc = dfmt.data.d3d_curvedbend_trim(return_filepath=True)
+
+    uds = dfmt.open_dataset_delft3d4(file_nc)
+
+    assert "mesh2d" in uds.grid.to_dataset().data_vars
+    assert "vertical_dimensions" in uds.grid.attrs
+    assert "grid" not in uds.data_vars
+
+    # test if plotting works, this is a basic validation of whether it is a proper ugrid dataset
+    uds.umag.isel(time=-1, KMAXOUT_RESTR=-1).ugrid.plot()