Street-network Sprawl in Chengannur, India

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:

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:

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

Chengannur: city in Kerala, India

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 Chengannur, India on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Chengannur as of 2014, the overall level of street-network sprawl is 3.4, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 4.55, 2.88, 5.01 and 4.9. Disconnectivity in street construction in Chengannur follows a zig-zag trend. In 1976-1990, street construction was most disconnected, while construction was most connected in 1991-2000.

Quantity of street network construction: The street network in Chengannur spans a total of 85 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 2.88, which is in the 40th to 60th percentile of disconnectedness.

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 4.55, 3.08, 3.24 and 3.4. The SNDi of the aggregate street network in fell at first, but Chengannur has worsened in disconnectivity since 1990.

Chengannur and Kerala follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these followed a zig-zag trend with an overall increase.

How do development practices in Chengannur fare in comparison to others in Kerala? Most recently in 2001-2014, street construction in Chengannur was the 22nd-most disconnected out of the 59 cities in Kerala. Its position in the ranks since 1975 has fallen; relative to other cities in Kerala, street construction in Chengannur has become more connected. Chengannur ranked 11th in 1975, 33rd in 1976-1990, 17th in 1991-2000 and 22nd in 2001-2014.

Chengannur and India do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Chengannur followed a zig-zag trend with an overall increase, while the SNDi of street constructions in India rose steadily.

How do development practices in Chengannur fare in comparison to others in India? Most recently in 2001-2014, street construction in Chengannur was the 258th-most disconnected out of the 1716 cities in India. Its position in the ranks since 1975 has fallen; relative to other cities in India, street construction in Chengannur has become more connected. Chengannur ranked 117th in 1975, 479th in 1976-1990, 184th in 1991-2000 and 258th in 2001-2014.

Chengannur and Kerala follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these was at its lowest in 1976-1990.

To date, Chengannur is the 33rd-most disconnected out of the 59 cities in Kerala. Its position in the ranks since 1975 has fallen; relative to other cities in Kerala, the street network in Chengannur has become more connected. Chengannur ranked 11th in 1975, 31st in 1976-1990, 32nd in 1991-2000 and 33rd in 2001-2014.

Chengannur and India do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Chengannur was at its lowest in 1976-1990, while the SNDi of street constructions in India rose steadily.

To date, Chengannur is the 497th-most disconnected out of the 1716 cities in India. Its position in the ranks since 1975 has fallen; relative to other cities in India, the street network in Chengannur has become more connected. Chengannur ranked 117th in 1975, 426th in 1976-1990, 458th in 1991-2000 and 497th in 2001-2014.

As of 2015, Chengannur had a built-up area of 4.4 square kilometers, and a population of 74044 people.

These are some other cities with approximately the same population: