Assignment 3

Assignment 3#

Download the data for the assignment from here. There are two datasets in this folder. The first, grahph.graphml, is a full-featured OSMnx/NetworkX graph constructed from a shapefile of the North Carolina primary and secondary road network. The second, tl_2019_37_place_centroids, is a shapefile containing centroids of all places in North Carolina (i.e. as points). The Census Bureau defines a place as an incorporated city, town, village, or borough.

../_images/highway.jpg

Task 1 (10 points)#

Read the graph dataset using the following code:

import geopandas as gpd
import osmnx as ox
import networkx as nx

graph = ox.load_graphml('path/to/data/graph.graphml')

  • a) How many nodes and edges does this graph have?

  • b) Convert the graph to two GeoDataFrames, one containing edges and one containing the nodes.

Click to reveal hint

ox.graph_to_gdfs(graph, nodes=True, edges=False) will provide the nodes.

  • c) What is the coordinate reference system of the nodes GeoDataFrame?

  • d) List the column names in the edges GeoDataFrame.

  • e) What is the min, max, and mean edge length?

  • f) Produce and customize a plot showing the North Carolina road network using the ox.plot_graph function.

Task 2 (10 points)#

Read the tl_2019_37_place_centroids.shp using GeoPandas.

  • a) Reproject the city GeoDataFrame to UTM Zone 17 N.

  • b) Choose four cities in North Carolina (the more spread out the better!) and compute the Euclidean distance (in km) between each pair.

  • c) List the nearest node for each of the four cities.

  • d) What is the shortest path length (i.e. nx.shortest_path_length) between three pairs of cities (in km)?

  • e) Produce and customize a plot showing the routes between your three city pairs (i.e. fig, ax = ox.plot_graph_route(graph, route)).

Note

ox.plot_route_folium probably will not work because the graph is not projected in the expected WGS84 coordinate system (i.e. EPSG:4326).

  • f) On average, how much longer is the network distances compared to the equivalent Euclidean distances?

  • g) How long would it take to travel between your three city pairs given an average speed of 60 mph?

Task 3 (5 points)#

  • How many cities in North Carolina are within a 2 hour drive of Durham (at 60 mph)?

Important

Save your notebooks locally as both .ipynb and .pdf formats but only submit the pdf to Canvas.