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# Query the graph, calculates the wegiht, then read the data the Dijstars Graph() class
graphQuery = """
-- Forwards, from start to end
SELECT start_node as node1, end_node as node2, split_way_id,
CASE
WHEN json_extract(tags, '$.oneway') == '-1' THEN 10000000000.0
ELSE length_m
END as cost
FROM osm_network_graph
WHERE json_extract(tags, '$.highway') IN {0}
UNION
-- Backwards, from end to start
SELECT end_node as node1, start_node as node2, split_way_id,
CASE
WHEN json_extract(tags, '$.oneway') == 'yes' THEN 10000000000.0
ELSE length_m
END as cost
FROM osm_network_graph
WHERE json_extract(tags, '$.highway') IN {0};""".format(str(tuple(Vehicle)))
cursor.execute(graphQuery)
# Define Graph() Object
osmGraph = Graph()
[osmGraph.add_edge(item[0],item[1],{'edge_id':item[2],'cost':item[3]}) for item in cursor.fetchall()]
# Define a function that will be applied to the graph to return the cost of each edge
cost_func = cost_func = lambda u, v, e, prev_e: e['cost']
# Solve from Starting Node To End Node
PointA = 3415159798 # National Stadium - Washington, DC
PointB = 2179757650 # John F. Kennedy Center, Washington DC
try:
path = find_path(graph=osmGraph, s=PointA,d=PointB,cost_func=cost_func)
# Collect Edge Ids
edges = [edge['edge_id'] for edge in path.edges]
# Create a GeoPackageView Of Route
routeSeqence = ''.join(['WHEN osm.split_way_id={} THEN {} '.format(edges[i],i) for i in range(len(edges))])
try:
createView = """CREATE VIEW route AS
SELECT CASE {0} END AS route_sequence, osm.*
FROM osm_network_graph osm
WHERE osm.split_way_id IN {1}""".format(routeSeqence,str(tuple(edges)))
insertToGpkgContents = """INSERT INTO gpkg_contents (table_name, identifier, data_type, srs_id)
VALUES('route','route','features',4326)"""
insertToGpkgGeometryColumn ="""INSERT INTO gpkg_geometry_columns (table_name, column_name, geometry_type_name, srs_id, z, m)
VALUES ('route', 'geom', 'LINESTRING', 4326, 0, 0)"""
cursor.execute(createView)
cursor.execute(insertToGpkgGeometryColumn)
cursor.execute(insertToGpkgContents)
databaseConnection.commit()
except sqlite3.OperationalError:
print('View Currently Exists')
databaseConnection.close()
# Execpt error is no path is found
except NoPathError:
print('No Path Found')
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