refactor element_as_gdf internals

spaghetti/network.py

@@ -3060,7 +3060,6 @@ def element_as_gdf(
     snapped=False,
     routes=None,
     id_col="id",
-    geom_col="geometry",
 ):
     """Return a ``geopandas.GeoDataFrame`` of network elements. This can be
     (a) the vertices of a network; (b) the arcs of a network; (c) both the
@@ -3088,9 +3087,6 @@ def element_as_gdf(
     id_col : str
         ``geopandas.GeoDataFrame`` column name for IDs. Default is ``"id"``.
         When extracting routes this creates an (origin, destination) tuple.
-    geom_col : str
-        ``geopandas.GeoDataFrame`` column name for geometry. Default is
-        ``"geometry"``.
 
     Raises
     ------
@@ -3165,7 +3161,7 @@ def element_as_gdf(
 
     # shortest path routes between observations
     if routes:
-        paths = util._routes_as_gdf(routes, id_col, geom_col)
+        paths = util._routes_as_gdf(routes, id_col)
         return paths
 
     # need vertices place holder to create network segment LineStrings
@@ -3183,7 +3179,6 @@ def element_as_gdf(
             pp_name,
             snapped,
             id_col=id_col,
-            geom_col=geom_col,
         )
 
         # return points geodataframe if arcs not specified or
@@ -3192,7 +3187,7 @@ def element_as_gdf(
             return points
 
     # arcs
-    arcs = util._arcs_as_gdf(net, points, id_col=id_col, geom_col=geom_col)
+    arcs = util._arcs_as_gdf(net, points, id_col=id_col)
 
     if vertices_for_arcs:
         return arcs

spaghetti/tests/test_network.py

@@ -493,7 +493,7 @@ def test_element_as_gdf(self):
         _, tree = ntw.allneighbordistances(points1, points2, gen_tree=True)
         paths = ntw.shortest_paths(tree, points1, pp_dest=points2)
         paths_gdf = spaghetti.element_as_gdf(ntw, routes=paths)
-        observed_origins = paths_gdf["O"].nunique()
+        observed_origins = paths_gdf["id"].map(lambda x: x[0]).nunique()
         assert observed_origins == known_origins
 
     def test_regular_lattice(self):

spaghetti/util.py

@@ -7,6 +7,7 @@
 
 try:
     import geopandas
+    import pandas
     import shapely
     from shapely.geometry import LineString
 except ImportError:
@@ -659,9 +660,7 @@ def build_chains(space_h, space_v, exterior, bounds, h=True):
 
 
 @requires("geopandas", "shapely")
-def _points_as_gdf(
-    net, vertices, vertices_for_arcs, pp_name, snapped, id_col=None, geom_col=None
-):
+def _points_as_gdf(net, vertices, vertices_for_arcs, pp_name, snapped, id_col=None):
     """Internal function for returning a point ``geopandas.GeoDataFrame``
     called from within ``spaghetti.element_as_gdf()``.
 
@@ -743,7 +742,7 @@ def _points_as_gdf(
 
 
 @requires("geopandas", "shapely")
-def _arcs_as_gdf(net, points, id_col=None, geom_col=None):
+def _arcs_as_gdf(net, points, id_col=None):
     """Internal function for returning an arc ``geopandas.GeoDataFrame``
     called from within ``spaghetti.element_as_gdf()``.
 
@@ -762,20 +761,16 @@ def _arcs_as_gdf(net, points, id_col=None, geom_col=None):
 
     """
 
-    # arcs
-    arcs = {}
-
-    # iterate over network arcs
-    for vtx1_id, vtx2_id in net.arcs:
-        # extract vertices comprising the network arc
-        vtx1 = points.loc[(points[id_col] == vtx1_id), geom_col].squeeze()
-        vtx2 = points.loc[(points[id_col] == vtx2_id), geom_col].squeeze()
-        # create a LineString for the network arc
-        arcs[(vtx1_id, vtx2_id)] = LineString((vtx1, vtx2))
+    def _line_coords(loc):
+        return (
+            (points.loc[loc[0]].geometry.x, points.loc[loc[0]].geometry.y),
+            (points.loc[loc[1]].geometry.x, points.loc[loc[1]].geometry.y),
+        )
 
     # instantiate GeoDataFrame
-    arcs = geopandas.GeoDataFrame(
-        sorted(list(arcs.items())), columns=[id_col, geom_col]
+    arcs = pandas.DataFrame(zip(sorted(net.arcs)), columns=[id_col])
+    arcs = arcs.set_geometry(
+        shapely.linestrings(arcs[id_col].map(_line_coords).values.tolist())
     )
 
     # additional columns
@@ -786,7 +781,7 @@ def _arcs_as_gdf(net, points, id_col=None, geom_col=None):
 
 
 @requires("geopandas", "shapely")
-def _routes_as_gdf(paths, id_col, geom_col):
+def _routes_as_gdf(paths, id_col):
     """Internal function for returning a shortest paths
     ``geopandas.GeoDataFrame`` called from within
     ``spaghetti.element_as_gdf()``.
@@ -807,17 +802,9 @@ def _routes_as_gdf(paths, id_col, geom_col):
 
     """
 
-    # isolate the origins, destinations, and geometries
-    origs = [o for (o, d), g in paths]
-    dests = [d for (o, d), g in paths]
-    geoms = [LineString(g.vertices) for (o, d), g in paths]
-
     # instantiate as a geodataframe
-    paths = geopandas.GeoDataFrame(geometry=geoms)
-    paths["O"] = origs
-    paths["D"] = dests
-
-    if id_col:
-        paths[id_col] = paths.apply(lambda x: (x["O"], x["D"]), axis=1)
+    paths = dict(paths)
+    ids, geoms = zip(paths.keys()), [LineString(g.vertices) for g in paths.values()]
+    paths = geopandas.GeoDataFrame(ids, columns=[id_col], geometry=geoms)
 
     return paths