Cities Morphology

The size and shape of cities matter. They affect the travel distances of its city inhabitants, the total energy consumption of a city, and the area a city consumes. Cities Morphology lets you construct towns and cities based on basic variables like shape, size, and density and illustrates the effects on travel distance, energy consumption, and area.

Simulating Different Cities

To visualize the effect the shape of a city has on its energy consumption, we can alter important properties of virtual cities and run simulations.

In the visualization, each ball represents an agent. The number of agents corresponds to the inhabitants of our city. Each agent travels between a starting and endpoint. The colors of the balls show the travel distances. Agents with a long journey are shown in red, whereas agents with a shorter journey are shown in blue. Additionally, we show the average travel distance for each street.

When we look at all agents, we can compute our virtual city's average travel distance. Additionally, the accumulated travel distances can also serve as a proxy for the city's energy consumption.

In the visualization, an efficient compact city with short travel distances will have many agents and streets colored blue. In contrast, a city with more sprawl will have more red agents and streets. Let's manipulate the parameters of our city one by one to see how they affect travel distance and energy consumption.

Number of Inhabitants

We start by manipulating the number of people living in a city. Notice that a corresponding city is constructed—if you increase the inhabitants, the city gets more buildings.

The more people live in a city, the more energy there is for transport. It can be estimated that when a city doubles its population, its energy demand from transport triples.

Dense or Sprawl

The space between buildings also affects a city's efficiency and footprint. Increasing the space between buildings also drastically increases the average travel distance of our inhabitants.

Circular or Elongated

You can also change the cities elongation. An elongation value of 1 corresponds to a circular city, and higher values correspond to cities shaped like ellipses. As you can see in the chart below, the more stretched a city gets, the longer the travel distances in that city.

Size of Buildings

The average travel distance of inhabitants is also greatly affected by the shape of the city's buildings. A city where many people live in buildings with multiple floors requires fewer buildings to house the city's population. This results in shorter travel distances compared to a city where, on average, two persons live in a building.

Profile of a City

In the simulation, you can also change whether all buildings are equal in height or whether buildings in the center house more people than those located further away from the center. A city with a profile value = 0 is shaped like a disk, where all houses are equal in height. A value of 0.8 results in a city shaped like a pyramid with higher central buildings.