Street-network Sprawl in Noakhali, Bangladesh

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.

Noakhali: city in Chittagong, Bangladesh

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 Noakhali, Bangladesh on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Noakhali as of 2014, the overall level of street-network sprawl is 5.48, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 4.06, 6.06, 5.23 and 3.45. Street construction in Noakhali increased in disconnectivity initially but has since improved. The streets constructed in 1976-1990 were the most disconnected.

Quantity of street network construction: The street network in Noakhali spans a total of 355 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 6.06, which is highly disconnected.

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 4.06, 5.83, 5.8 and 5.48. The aggregate street network in Noakhali increased in disconnectivity initially,but the trend has turned around after 1990.

Noakhali and Chittagong do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Noakhali peaked in 1976-1990, while the SNDi of street constructions in Chittagong peaked in 1991-2000.

How do development practices in Noakhali fare in comparison to others in Chittagong? Most recently in 2001-2014, street construction in Noakhali was the 8th-most disconnected out of the 21 cities in Chittagong. Its position in the ranks since 1975 has risen; relative to other cities in Chittagong, street construction in Noakhali has become more disconnected. Noakhali ranked 9th in 1975, 5th in 1976-1990, 8th in 1991-2000 and 8th in 2001-2014.

Noakhali and Bangladesh do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Noakhali peaked in 1976-1990, while the SNDi of street constructions in Bangladesh rose steadily.

How do development practices in Noakhali fare in comparison to others in Bangladesh? Most recently in 2001-2014, street construction in Noakhali was the 60th-most disconnected out of the 157 cities in Bangladesh. Its position in the ranks since 1975 has fallen; relative to other cities in Bangladesh, street construction in Noakhali has become more connected. Noakhali ranked 23rd in 1975, 11th in 1976-1990, 30th in 1991-2000 and 60th in 2001-2014.

Noakhali and Chittagong follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these peaked in 1976-1990.

To date, Noakhali is the 10th-most disconnected out of the 21 cities in Chittagong. Its position in the ranks since 1975 has fallen; relative to other cities in Chittagong, the street network in Noakhali has become more connected. Noakhali ranked 9th in 1975, 6th in 1976-1990, 7th in 1991-2000 and 10th in 2001-2014.

Noakhali and Bangladesh do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Noakhali peaked in 1976-1990, while the SNDi of street constructions in Bangladesh rose steadily.

To date, Noakhali is the 29th-most disconnected out of the 157 cities in Bangladesh. Its position in the ranks since 1975 has fallen; relative to other cities in Bangladesh, the street network in Noakhali has become more connected. Noakhali ranked 23rd in 1975, 13th in 1976-1990, 19th in 1991-2000 and 29th in 2001-2014.

As of 2015, Noakhali had a built-up area of 107.56 square kilometers, and a population of 2006142 people.

These are some other cities with approximately the same population: