Street-network Sprawl in Chalus, Iran

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.

Chalus: city in Mazandaran, Iran

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 Chalus, Iran on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Chalus as of 2014, the overall level of street-network sprawl is 7.79, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 8.16, 6.78, 10.0 and 10.49. The disconnectivity of new streets constructed in Chalus fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Chalus spans a total of 713 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 8.16, 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 8.16, 7.66, 7.71 and 7.79. The SNDi of the aggregate street network in fell at first, but Chalus has worsened in disconnectivity since 1990.

Chalus and Mazandaran do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Chalus was at its lowest in 1976-1990, while the SNDi of street constructions in Mazandaran rose steadily.

How do development practices in Chalus fare in comparison to others in Mazandaran? Most recently in 2001-2014, street construction in Chalus was the 1st-most disconnected out of the 7 cities in Mazandaran. Its position in the ranks since 1975 has not changed. Chalus ranked 1st in 1975, 1st in 1976-1990, 3rd in 1991-2000 and 1st in 2001-2014.

Chalus and Iran follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these was at its lowest in 1976-1990.

How do development practices in Chalus fare in comparison to others in Iran? Most recently in 2001-2014, street construction in Chalus was the 2nd-most disconnected out of the 181 cities in Iran. Its position in the ranks since 1975 has risen; relative to other cities in Iran, street construction in Chalus has become more disconnected. Chalus ranked 4th in 1975, 1st in 1976-1990, 3rd in 1991-2000 and 2nd in 2001-2014.

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

To date, Chalus is the 1st-most disconnected out of the 7 cities in Mazandaran. Its position in the ranks since 1975 has not changed. Chalus ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014.

Chalus and Iran 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, Chalus is the 1st-most disconnected out of the 181 cities in Iran. Its position in the ranks since 1975 has risen; relative to other cities in Iran, the street network in Chalus has become more disconnected. Chalus ranked 4th in 1975, 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014.

As of 2015, Chalus had a built-up area of 32.25 square kilometers, and a population of 142937 people.

These are some other cities with approximately the same population: