Street-network Sprawl in Astara, 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.

Astara: city in Gilan, 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 Astara, Iran on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Astara as of 2014, the overall level of street-network sprawl is 3.68, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 3.82, 1.59, 6.8 and 1.94. Disconnectivity in street construction in Astara 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 Astara spans a total of 150 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 3.82, 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 3.82, 3.66, 3.74 and 3.68. Disconnectivity in Astara's street network follows a zig-zag trend. In 1976-1990, the city was most disconnected; while it was most connected in 1975.

Astara and Gilan 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 decrease.

How do development practices in Astara fare in comparison to others in Gilan? Most recently in 2001-2014, street construction in Astara was the 5th-most disconnected out of the 6 cities in Gilan. Its position in the ranks since 1975 has fallen; relative to other cities in Gilan, street construction in Astara has become more connected. Astara ranked 2nd in 1975, 5th in 1976-1990, 1st in 1991-2000 and 5th in 2001-2014.

Astara and Iran do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Astara followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in Iran was at its lowest in 1976-1990.

How do development practices in Astara fare in comparison to others in Iran? Most recently in 2001-2014, street construction in Astara was the 129th-most disconnected out of the 181 cities in Iran. Its position in the ranks since 1975 has fallen; relative to other cities in Iran, street construction in Astara has become more connected. Astara ranked 31st in 1975, 91st in 1976-1990, 6th in 1991-2000 and 129th in 2001-2014.

Astara and Gilan do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Astara followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in Gilan was at its lowest in 1976-1990.

To date, Astara is the 2nd-most disconnected out of the 6 cities in Gilan. Its position in the ranks since 1975 has not changed. Astara ranked 2nd in 1975, 2nd in 1976-1990, 2nd in 1991-2000 and 2nd in 2001-2014.

Astara and Iran do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Astara followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in Iran was at its lowest in 1976-1990.

To date, Astara is the 23rd-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 Astara has become more disconnected. Astara ranked 31st in 1975, 18th in 1976-1990, 18th in 1991-2000 and 23rd in 2001-2014.

As of 2015, Astara had a built-up area of 2.13 square kilometers, and a population of 65662 people.

These are some other cities with approximately the same population: