Pandana Network Store from Shapefile

generate_pdna_store_from_shp.py

# This GIST provides a template for conveting shapefiles into pandana networks. 
# Under a MIT Open Source License. https://opensource.org/licenses/MIT
# Researchers cite as Wasserman, D. Geopandas to Pandana Network Converter. (2019) GitHub repository, https://gist.github.com/d-wasserman/2d50671b37ee46b088e155293399a90c

def get_nodes_and_edges(shp_file,rounding=5):
    """Use geopandas to read line shapefile and compile all paths and nodes in a line file based on a rounding tolerance.
    shp_file:path to polyline file with end to end connectivity
    rounding: tolerance parameter for coordinate precision"""
    edges = gpd.read_file(shp_file)
    edges["from_x"]=edges["geometry"].apply(lambda x:round(x.coords[0][0],rounding))
    edges["from_y"]=edges["geometry"].apply(lambda x:round(x.coords[0][1],rounding))
    edges["to_x"]=edges["geometry"].apply(lambda x:round(x.coords[-1][0],rounding))
    edges["to_y"]=edges["geometry"].apply(lambda x:round(x.coords[-1][1],rounding))
    nodes_from = edges[["from_x","from_y"]].rename(index=str,columns={"from_x":"x","from_y":"y"})
    nodes_to = edges[["to_x","to_y"]].rename(index=str,columns={"to_x":"x","to_y":"y"})
    nodes = pd.concat([nodes_from,nodes_to],axis=0)
    nodes["xy"] = list(zip(nodes["x"], nodes["y"]))
    nodes = pd.DataFrame(nodes["xy"].unique(),columns=["xy"])
    nodes["x"] = nodes["xy"].apply(lambda x: x[0])
    nodes["y"] = nodes["xy"].apply(lambda x: x[1])
    nodes = nodes[["x","y"]].copy()
    return nodes , edges

def generate_pandana_store_from_shp(hdf5_path, shp_file, weights=["weight"], oneway=None, overwrite_existing=True,
                                    rounding=6):
    """Generate a pandana ready HDF5 store using geopandas (gdal required) and pandas. Function assumes shape file has
    the appropriate topology where each edge has end points that lead to nodes. If using OSM, pre-process with Osmnx.
     Python 3.5.
        Parameters
        ----------
        hdf5_path: str  
            output path of HDF5 store holding two dataframes ["nodes","edges"]
        shp_file: str 
            input file that geopandas reads to make a graph based on end to end connectivity
        weights : lists
            weights columns transfered to the store edges. Name is maintained.
        oneway: str
            series name where oneway streets (edges) are denoted with a 1, 0 denotes twoway. None, assumes twoway edge.
        overwrite_existing: boolean
            if true, the existing store is overwritten.
        rounding:int  
            the number of digits to round line coordinates to get unique nodes (precision)
        Returns
        -----------
            hdf5_path:basestring - path of output hdf5 pandana store."""
    if os.path.exists(hdf5_path):
        if overwrite_existing:
            print("Overwriting existing store...")
            os.remove(hdf5_path)
        else:
            print("Existing store at path: {0}".format(hdf5_path))
            return hdf5_path
    all_edges_twoway = True
    oneway_field_list = []
    if oneway is not None:
        all_edges_twoway = False
        oneway_field_list.append(oneway)
    print("Reading shapefile with geopandas: {0}...".format(shp_file))
    nodes, edges = get_nodes_and_edges(shp_file, rounding)
    h5store = pd.HDFStore(hdf5_path)
    print("Establishing node store...")
    df_nodes = nodes
    df_nodes["id"] = df_nodes.index.values
    df_nodes.index.rename("id", True)
    h5store['nodes'] = df_nodes
    edge_cnt = len(edges)
    print("Establishing edge store for {0} edges...".format(edge_cnt))
    df_edges = edges[['from_x', 'from_y', 'to_x', 'to_y'] + weights + oneway_field_list].copy()
    print("Transferring nodeids to edges...")
    df_edges = pd.merge(df_edges, df_nodes, how='left', left_on=['from_x', 'from_y'], right_on=['x', 'y'])
    df_edges = pd.merge(df_edges, df_nodes, how='left', left_on=['to_x', 'to_y'], right_on=['x', 'y'],
                        suffixes=('_from', '_to'))
    # nodeids are duplicated on from the joined nodes, joined first to from, suffix to on next set
    df_edges.rename(columns={'id_from': 'from', 'id_to': 'to'}, inplace=True)
    df_edges = df_edges[['from', 'to'] + weights + oneway_field_list]
    if all_edges_twoway:
        print("""Note: Edges are duplicated in this step, do not use the 'twoway' setting in the pandana network if using this 
             function""")
        twoway_edges = df_edges.copy()
        twoway_to = twoway_edges["to"].copy()
        twoway_edges["to"] = twoway_edges["from"]
        twoway_edges["from"] = twoway_to
        df_edges = pd.concat([df_edges, twoway_edges])
    else:
        print("Setting up edges based on oneway field...")
        twoway_edges = df_edges[df_edges[oneway] == 0].copy()
        twoway_to = twoway_edges["to"].copy()
        twoway_edges["to"] = twoway_edges["from"]
        twoway_edges["from"] = twoway_to
        df_edges = pd.concat([df_edges, twoway_edges])
    h5store['edges'] = df_edges
    h5store.close()
    print("Graph store construction complete...")
    return hdf5_path

This makes sense! Thanks for sharing. I think I need to make a version just to take osmnx edges, but that should be straight forward.