netcdf: add mf6 model

docs/examples/twri.py

@@ -285,7 +285,8 @@ def plot_head(head, workspace):
 nc_fpth = workspace / "twri.input.nc"
 gwf.netcdf_file = nc_fpth
 
-ds = gwf.to_xarray(format="structured")
+nc_model = flopy4.mf6.netcdf.NetCDFModel.from_model(gwf)
+ds = nc_model.to_xarray()
 ds.to_netcdf(nc_fpth)
 
 with flopy4.mf6.write_context.WriteContext(use_netcdf=True):
@@ -303,7 +304,8 @@ def plot_head(head, workspace):
 nc_fpth = workspace / "twri.input.nc"
 gwf.netcdf_file = nc_fpth
 
-ds = gwf.to_xarray(format="layered")
+nc_model = flopy4.mf6.netcdf.NetCDFModel.from_model(gwf, mesh="layered")
+ds = nc_model.to_xarray()
 ds.to_netcdf(nc_fpth)
 
 with flopy4.mf6.write_context.WriteContext(use_netcdf=True):

flopy4/mf6/__init__.py

@@ -12,11 +12,12 @@
 from flopy4.mf6.component import Component
 from flopy4.mf6.converter import structure, unstructure
 from flopy4.mf6.ims import Ims
+from flopy4.mf6.netcdf import NetCDFModel
 from flopy4.mf6.simulation import Simulation
 from flopy4.mf6.tdis import Tdis
 from flopy4.uio import DEFAULT_REGISTRY
 
-__all__ = ["gwf", "simulation", "solution", "utils", "Ims", "Tdis", "Simulation"]
+__all__ = ["gwf", "simulation", "solution", "utils", "Ims", "NetCDFModel", "Tdis", "Simulation"]
 
 
 class WriteError(Exception):

flopy4/mf6/model.py

@@ -1,6 +1,5 @@
 from abc import ABC
 
-import xarray as xr
 from xattree import xattree
 
 from flopy4.mf6.context import Context
@@ -10,15 +9,3 @@
 class Model(Context, ABC):
     def default_filename(self) -> str:
         return f"{self.name}.nam"  # type: ignore
-
-    def to_xarray(self, format: str | None = None) -> xr.Dataset:
-        from flopy4.mf6.converter.egress.dataset import xarray_flat
-
-        dt = super().to_xarray()
-        if format is not None:
-            mesh_type = None
-            if format.lower() == "layered":
-                mesh_type = "layered"
-            return xarray_flat(dt, mesh_type)
-        else:
-            return dt