spaghetti.element_as_gdf

spaghetti.element_as_gdf(net, vertices=False, arcs=False, pp_name=None, snapped=False, routes=None, id_col='id', geom_col=None)

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 vertices and arcs of the network; (d) the raw point pattern associated with the network; (e) the snapped point pattern of (d); or (f) the shortest path routes between point observations.

Parameters:

netspaghetti.Network

A spaghetti network object.

verticesbool

Extract the network vertices (True). Default is False.

arcsbool

Extract the network arcs (True). Default is False.

pp_namestr

Name of the network.PointPattern to extract. Default is None.

snappedbool

If extracting a network.PointPattern, set to True for snapped point locations along the network. Default is False.

routesdict

See paths from spaghetti.Network.shortest_paths. Default is None.

id_colstr

geopandas.GeoDataFrame column name for IDs. Default is "id". When extracting routes this creates an (origin, destination) tuple.

geom_colstr

Deprecated and will be removed in the minor release. geopandas.GeoDataFrame column name for IDs. Default is "id". When extracting routes this creates an (origin, destination) tuple.

Returns:

pointsgeopandas.GeoDataFrame

Network point elements (either vertices or network.PointPattern points) as a geopandas.GeoDataFrame of shapely.geometry.Point objects with an "id" column and "geometry"" column. If the network object has a network_component_vertices attribute, then component labels are also added in a column.

linesgeopandas.GeoDataFrame

Network arc elements as a geopandas.GeoDataFrame of shapely.geometry.LineString objects with an "id" column and "geometry" column. If the network object has a network_component_labels attribute, then component labels are also added in a column.

pathsgeopandas.GeoDataFrame

Shortest path routes along network arc elements as a geopandas.GeoDataFrame of shapely.geometry.LineString objects with an "id" (see spaghetti.Network.shortest_paths()) column and "geometry" column.

Raises:

KeyError

In order to extract a network.PointPattern it must already be a part of the network object. This exception is raised when a network.PointPattern is being extracted that does not exist within the network object.

See also

geopandas.GeoDataFrame

Notes

When both network vertices and arcs are desired, the variable declaration must be in the order: <vertices>, <arcs>.

Examples

Instantiate a network object.

>>> import spaghetti
>>> from libpysal import examples
>>> ntw = spaghetti.Network(examples.get_path("streets.shp"))

Extract the network elements (vertices and arcs) as geopandas.GeoDataFrame objects.

>>> vertices_df, arcs_df = spaghetti.element_as_gdf(
...     ntw, vertices=True, arcs=True
... )

Examine the first vertex. It is a member of the component labeled 0.

>>> vertices_df.loc[0]
id                                            0
geometry      POINT (728368.04762 877125.89535)
comp_label                                    0
Name: 0, dtype: object

Calculate the total length of the network.

>>> arcs_df.geometry.length.sum()
np.float64(104414.09200823458)