Quantifying Walkability: Measuring Network Length

One of the fundamental aspects of walkability is the physical length of pedestrian pathways within a city. In this section, we introduce a function that calculates and quantifies the total length of the pedestrian network in kilometers.

Measuring Network Length

The following Python function, get_network_length_km(graph), takes the extracted pedestrian network graph (graph) as input and computes the total length of network edges in kilometers. Let's break down the code:

    
# Compute the total length of network edges in kmeters

def get_network_length_km(graph):
    # Initialize variables to store total length
    total_length_meters = 0.0

    # Calculate the total length of network edges in meters
    for u, v, data in graph.edges(data=True):
        if 'length' in data:  # Check if 'length' attribute exists
            total_length_meters += data['length']
    # Convert to kilometers
    total_length_km = total_length_meters / 1000

    # Print the total length in kilometers
    print(f"Total length of network edges (km): {total_length_km}")
    return total_length_km
        
    
    
G_total_length_km=get_network_length_km(G)
    
    
Total length of network edges (km): 27186.319582000375
    

Understanding the Function

										
1. Initialization: The function starts by initializing a variable (total_length_meters) 
to store the cumulative length of all network edges. 

2. Calculating Length: It then iterates through each edge in the network, checking if the 'length' attribute exists 
in the edge data. If so, it adds the length to the total. 

3. Conversion: The total length is initially measured in meters and is then converted to kilometers. 

4. Print and Return: Finally, the function prints the total length in kilometers 
and returns this value for further analysis. 
		
	

Application in Walkability Analysis

Measuring the network length is a critical step in understanding the extent of walkable pathways within the city.