turns out rounding is sufficient, no need for final filtering step

autotest/test_gridgen.py

@@ -888,10 +888,8 @@ def test_flopy_issue_1492(function_tmpdir):
     )
     og_grid = gwf.modelgrid
 
-    # Create and build the gridgen model with a refined area in the middle
+    # Create and build the gridgen model
     g = Gridgen(dis, model_ws=function_tmpdir)
-    # polys = [Polygon([(4, 4), (6, 4), (6, 6), (4, 6)])]
-    # g.add_refinement_features(polys, "polygon", 3, range(nlay))
     g.build()
 
     # retrieve a dictionary of arguments to be passed
@@ -935,19 +933,16 @@ def test_flopy_issue_1492(function_tmpdir):
     success, _ = sim.run_simulation(silent=False)
     assert success
 
-    head = gwf.output.head().get_data()
-    bud = gwf.output.budget()
-    spdis = bud.get_data(text="DATA-SPDIS")[0]
+    # debugging duplicate vertices
     grid = gwf.modelgrid
-    og_verts = pd.DataFrame(
-        og_grid.verts, columns=["x", "y"]
-    )  # .round(3).sort_values(by=["x", "y"], ignore_index=True).drop_duplicates(ignore_index=True)
-    mg_verts = pd.DataFrame(
-        grid.verts, columns=["x", "y"]
-    )  # .round(3).sort_values(by=["x", "y"], ignore_index=True).drop_duplicates(ignore_index=True)
+    og_verts = pd.DataFrame(og_grid.verts, columns=["x", "y"])
+    mg_verts = pd.DataFrame(grid.verts, columns=["x", "y"])
 
     plot_debug = False
     if plot_debug:
+        head = gwf.output.head().get_data()
+        bud = gwf.output.budget()
+        spdis = bud.get_data(text="DATA-SPDIS")[0]
         pmv = flopy.plot.PlotMapView(gwf)
         pmv.plot_array(head)
         pmv.plot_grid(colors="white")

flopy/utils/cvfdutil.py

@@ -183,7 +183,10 @@ def to_cvfd(
         xcyc[icell, 1] = yc
         ivertlist = []
         for p in points:
-            pt = (round(p[0], 9), round(p[1], 9))
+            pt = (
+                round(p[0], duplicate_decimals),
+                round(p[1], duplicate_decimals),
+            )
             if pt in vertexdict:
                 ivert = vertexdict[pt]
             else:
@@ -247,24 +250,8 @@ def to_cvfd(
         if verbose:
             print("Done checking for hanging nodes.")
 
-    # drop duplicate vertices
-    def filter_verts():
-        return (
-            pd.DataFrame(np.array(vertexdict_keys), columns=["x", "y"])
-            .round(duplicate_decimals)
-            .drop_duplicates(["x", "y"], ignore_index=False)
-            .to_numpy()
-        )
-
-    verts = filter_verts()
-
-    def filter_iverts():
-        vtups = [tuple(v) for v in verts.tolist()]
-        vdict = {k: v for k, v in vertexdict.items() if k in vtups}
-        for vl in vertexlist:
-            yield [v for v in vl if v in vdict.values()]
-
-    iverts = list(filter_iverts())
+    verts = np.array(vertexdict_keys)
+    iverts = vertexlist
 
     return verts, iverts
 

flopy/utils/gridgen.py

@@ -1891,9 +1891,7 @@ def _mkvertdict(self):
         idx = attributes.index("nodenumber")
         for i in range(len(shapes)):
             nodenumber = int(records[i][idx]) - 1
-            points = shapes[i].points
-            # import pdb; pdb.set_trace()
-            self._vertdict[nodenumber] = points
+            self._vertdict[nodenumber] = shapes[i].points
 
     @staticmethod
     def read_qtg_nod(