Street-network Sprawl in Puno, Peru

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What is Street-network sprawl?

Street-network Sprawl is a way to measure urban sprawl, worldwide, through the connectedness of the streets. Less sprawl means more connected, more walkable streets. Well-connected streets – like New York City’s grid – are more walkable and can be served by public transit.

The street network is permanent, and its connectivity affects the livability and environmental footprint of cities for decades and centuries to come. In places with more connected streets, residents drive less and walk more. A well-connected street network is associated with better outcomes for health, the environment, sustainable consumption, social integration, and equity.

We can quantify how connected street networks are with the Street Network Disconnectedness Index (SNDi).

SNDi -- our measure of street-network sprawl (disconnectedness)

The SNDi is a comprehensive measurement of “sprawl”. It captures:

• nodal degree
• dendricity, the tree-likeness of the street network
• circuity, the ratio of the distance by road to the straight-line distance of two locations on the street network
• sinuosity, the curviness of a street

A higher SNDi means less-connected streets – i.e., more sprawl. For the 10137 cities in our dataset, the average SNDi is 2.25, with half of the cities' SNDis falling between 1.08 and 3.25.

More information on the sprawl index can be found in these research papers:

• Global trends toward urban street-network sprawl
• A global assessment of street-network sprawl

To see the state of street-network sprawl across the globe, visit the sprawlmap.

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Puno: region in Peru

What exactly constitutes the spatial extent of the city? For these aggregations, we used the Global Human Settlement Layer Urban Center Database (GHS-UCDB) to define the boundaries of the city. These cities -- or urban centers -- cover areas that are densely populated and built-up, and so may extend beyond the spatial borders of these cities that we may be familiar with. The GHS area is shaded in blue.

View Puno, Peru on the sprawlmap

How have Puno's street networks changed over time?

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Puno as of 2014, the overall level of street-network sprawl is 1.42, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.11, 1.11, 2.33 and 2.58. The disconnectivity of new streets constructed in Puno fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Puno spans a total of 6922 kilometers. The period with the greatest volume of street construction was 1975. These roads have an SNDi of 1.11, which is relatively well-connected.

Effect on the aggregate network: New construction in each period adds to the total stock of streets, but does not change streets that have already been built. Therefore, it has a limited effect on the street network as a whole. The SNDis of the aggregate street network in the respective time periods are 1.11, 1.16, 1.29 and 1.42. Overall, the SNDi of the aggregate street network has risen: the street network in Puno has become more disconnected.

Puno in context: Street-network sprawl of new development

The level of street-network sprawl in new development in Puno was at its lowest in 1976-1990. To get a sense of how street development has changed in Puno, we can consider three of its most populous cities: Juliaca, Puno and Ilave. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Juliaca rose steadily. The level of street-network sprawl in new development in Puno peaked in 1991-2000. The level of street-network sprawl in new development in Ilave followed a zig-zag trend with an overall increase.

How do development practices in Puno fare in comparison to others in Peru? Most recently in 2001-2014, street construction in Puno was the 19th-most disconnected out of the 23 regions in Peru. Its position in the ranks since 1975 has risen; relative to other regions in Peru, street construction in Puno has become more disconnected. Puno ranked 22nd in 1975, 8th in 1976-1990, 17th in 1991-2000 and 19th in 2001-2014.

Puno in context: Aggregate street-network sprawl

As of 2014, the city with the most disconnected street network in Puno is Puno with an SNDi of 1.0, which is relatively well-connected. Conversely, the most connected city is Ilave with an SNDi of -0.05, which is very well-connected. See trends for these cities: Ilave, Puno

The level of street-network sprawl in the aggregate network in Puno rose steadily. To get a sense of how the aggregate street network has changed in Puno, we can consider three of its most populous cities: Juliaca, Puno and Ilave. Disconnectivity in the most populous cities in Puno follow the same region trend.

To date, Puno is the 22nd-most disconnected out of the 23 regions in Peru. Its position in the ranks since 1975 has not changed. Puno ranked 22nd in 1975, 22nd in 1976-1990, 22nd in 1991-2000 and 22nd in 2001-2014.

Cities in Puno

• Juliaca
• Puno
• Ilave