fix(mflist_export): patch mf6 list data export

autotest/test_export.py

@@ -6,6 +6,7 @@
 import matplotlib.pyplot as plt
 import numpy as np
 import pytest
+import shapefile
 from flaky import flaky
 from modflow_devtools.markers import excludes_platform, requires_exe, requires_pkg
 from modflow_devtools.misc import has_pkg
@@ -2123,3 +2124,56 @@ def test_to_shapefile_raises_attributeerror():
     assert isinstance(spd, flopy.utils.MfList)
     with pytest.raises(AttributeError, match="was removed"):
         spd.to_shapefile("nope.shp", kper=1)
+
+
+@pytest.mark.mf6
+@requires_pkg("pyshp", name_map={"pyshp": "shapefile"})
+@pytest.mark.parametrize("use_pandas", [True])  # , False])
+@pytest.mark.parametrize("sparse", [True, False])
+def test_mf6_chd_shapefile_export(function_tmpdir, use_pandas, sparse):
+    from flopy.mf6 import (
+        MFSimulation,
+        ModflowGwf,
+        ModflowGwfchd,
+        ModflowGwfdis,
+        ModflowIms,
+        ModflowTdis,
+    )
+
+    # Create a simple structured grid MF6 model with CHD package
+    sim = MFSimulation(sim_name="mf6shp", sim_ws=function_tmpdir, use_pandas=use_pandas)
+    tdis = ModflowTdis(sim)
+    ims = ModflowIms(sim)
+    gwf = ModflowGwf(sim, modelname="gwf1", save_flows=True)
+    nlay, nrow, ncol = 1, 3, 3
+    dis = ModflowGwfdis(gwf, nlay=nlay, nrow=nrow, ncol=ncol, top=10.0, botm=0.0)
+    chd_cells = [((0, 0, 0), 1.0), ((0, 2, 2), 2.0)]
+    chd = ModflowGwfchd(gwf, stress_period_data=chd_cells)
+
+    # Export CHD package to shapefile
+    shpfile = function_tmpdir / f"chd_{use_pandas}_{sparse}.shp"
+    gwf.chd.stress_period_data.export(shpfile, sparse=sparse)
+
+    # Check that shapefile and sidecar files exist
+    for ext in [".shp", ".shx", ".dbf"]:
+        assert shpfile.with_suffix(ext).exists(), f"{shpfile.with_suffix(ext)} missing"
+
+    # Read shapefile and check records
+    with shapefile.Reader(str(shpfile)) as sf:
+        records = list(sf.records())
+        fields = [f[0] for f in sf.fields[1:]]  # skip DeletionFlag
+
+        if sparse:
+            # Only CHD cells should be exported
+            assert len(records) == len(chd_cells)
+        else:
+            # All grid cells should be exported
+            assert len(records) == nlay * nrow * ncol
+
+        # Check attribute values for CHD cells
+        chd_vals = [
+            rec[fields.index(next(f for f in fields if "head" in f))] for rec in records
+        ]
+        if sparse:
+            # Should match the CHD values
+            assert set(chd_vals) == {1.0, 2.0}

flopy/export/utils.py

@@ -5,6 +5,9 @@
 
 import numpy as np
 from packaging.version import Version
+from pandas import DataFrame
+
+from flopy.utils.util_list import MfList
 
 from ..datbase import DataInterface, DataListInterface, DataType
 from ..mbase import BaseModel, ModelInterface
@@ -896,15 +899,23 @@ def mflist_export(f: Union[str, os.PathLike, NetCdf], mfl, **kwargs):
             from ..export.shapefile_utils import recarray2shp
             from ..utils.geometry import Polygon
 
-            df = mfl.get_dataframe(squeeze=squeeze)
+            df = (
+                mfl.get_dataframe(squeeze=squeeze)
+                if isinstance(mfl, MfList)
+                else mfl.get_dataframe()
+            )
+            if isinstance(df, dict):
+                df = df[kper]
             if "kper" in kwargs or df is None:
                 ra = mfl[kper]
                 verts = np.array(modelgrid.get_cell_vertices(ra.i, ra.j))
             elif df is not None:
+                row_index_name = "i" if "i" in df.columns else "cellid_row"
+                col_index_name = "j" if "j" in df.columns else "cellid_column"
                 verts = np.array(
                     [
-                        modelgrid.get_cell_vertices(i, df.j.values[ix])
-                        for ix, i in enumerate(df.i.values)
+                        modelgrid.get_cell_vertices(i, df[col_index_name].values[ix])
+                        for ix, i in enumerate(df[row_index_name].values)
                     ]
                 )
                 ra = df.to_records(index=False)