Street-network Sprawl in Siirt, Turkey

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.

Siirt: city in Turkey

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 Siirt, Turkey on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Siirt as of 2014, the overall level of street-network sprawl is 1.1, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.3, 1.37, 0.99 and 4.08. Disconnectivity in street construction in Siirt follows a zig-zag trend. In 1975, street construction was most disconnected, while construction was most connected in 2001-2014.

Quantity of street network construction: The street network in Siirt spans a total of 254 kilometers. The period with the greatest volume of street construction was 1976-1990. These roads have an SNDi of 1.37, 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 0.3, 0.81, 0.84 and 1.1. Overall, the SNDi of the aggregate street network has risen: the street network in Siirt has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.51 points, but between 1991-2000 and 2001-2014, it rose by just 0.25.

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

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

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

How do development practices in Siirt fare in comparison to others in Turkey? Most recently in 2001-2014, street construction in Siirt was the 19th-most disconnected out of the 134 cities in Turkey. Its position in the ranks since 1975 has risen; relative to other cities in Turkey, street construction in Siirt has become more disconnected. Siirt ranked 90th in 1975, 48th in 1976-1990, 82nd in 1991-2000 and 19th in 2001-2014.

Siirt and Siirt follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

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

Siirt and Turkey follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Siirt is the 64th-most disconnected out of the 134 cities in Turkey. Its position in the ranks since 1975 has risen; relative to other cities in Turkey, the street network in Siirt has become more disconnected. Siirt ranked 90th in 1975, 76th in 1976-1990, 76th in 1991-2000 and 64th in 2001-2014.

As of 2015, Siirt had a built-up area of 5.12 square kilometers, and a population of 136100 people.

These are some other cities with approximately the same population: