Showing average Street-network Sprawl around the planet. Click on a country to zoom in.
Street-network Sprawl
Street-network Sprawl represents the disconnectivity of the street network covering the planet. It is measured through the connectivity of the urban street network calculated across countries, cities, and smaller geographies, and over time since 1975.
Data
This project is a collaboration between Professor Chris Barrington-Leigh at McGill University and Professor Adam Millard-Ball at the University of California, Santa Cruz.
We have more information online (in English), including tabular data for cities and countries, our research papers and our code.
Visit and join our discussion group to share interesting findings on this site. (Or see the 'Report an issue' link on the main page menu if you think you've found a problem.)
About
The sprawl index, or SNDi in our research papers, is our overall measure of street-network sprawl. It stands for the Street Network Disconnectedness Index. A higher SNDi means less-connected streets – i.e., more sprawl.
Under Advanced Controls (or the gear icon), you can choose to display some other measures of sprawl. They all make up part of our Index, and are all described in our research papers.
To see changes over time, open up the Advanced Controls (or gear icon). 'Show Stock' shows all streets (and SNDi) based on all urban streets. 'Show Cumulative' shows all streets (and the corresponding SNDi) built up to a given year, while turning it off shows just the streets (and their SNDi) that were built in a given time period. You can choose the time period with a slider.
Report an issue
If you have comments or find a problem with this web site, contact
(see sprawl.research.mcgill.ca) or report a problem on our discussion group.
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If you have comments or find a problem with this web site, contact
(see wellbeing.research.mcgill.ca) or directly report an issue on GitLab
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Welcome to the Global Sprawl Map
We measure sprawl through the connectivity of the streets. Sprawl is characterized by poorly connected streets – a maze of cul-de-sacs and loops, where people are dependent on private cars. These are the red areas on the map.
Well-connected streets – like New York City’s grid – are more walkable and can be served by public transit. These are the blue areas on the map.
To get started, click on a country, and then zoom in to your favourite places and see how they rank on our index of street-network sprawl.If you want to start with a lot more detail, you can read our research paper, or click on 'About' from the 'More' menu.
You can zoom in all the way to see our street-level data.
You can also look under the Advanced settings to see how things have changed over time. In many parts of the world, you will find a worrying trend.
And for fun, you can choose a random jump to a spot on the planet based on our eight types of street connectivity.
Orientation Changed
Advanced Controls
Choose a random jump
Measures of street-network sprawl
You can choose to display any of three features, but each of them is a measure of street-network sprawl. Higher (red) values mean more disconnected local streets. Lower (blue) values mean more connected local streets.
Sprawl index: This is the best overall measure. It is an index made up from thirteen features, described in our research paper, calculated based on each street intersection and street segment.
Circuity: This is a measure of how far you have to walk to get to nearby places. That is, it reflects how easily you can get to nearby places on the street network. The exact definition is available in our published research paper.
Curviness: This is not one of the most revealing features for our index, but it is interesting and may reflect stylistic differences from region to region. Curviness is simply a measure of how straight road segments are (ie, how much streets deviate, between intersections, from straight lines).
A legend shows the colour scale. It is used for the different levels of geographic resolution, starting with countries, as you zoom in.
If you zoom in enough, you will see the street network itself, which shows street segment classifications. That is a separate colour scale and does not correspond to the 'feature' chosen here.
'Show Stock' option
When 'Show Stock' is selected, the map will show street-network sprawl based on all existing roads.
When it is turned off, you can instead see the level of street-network sprawl for different time periods, ie based on when roads were built. In this mode, you will have further choices about which period to show.
'Show Cumulative' option
There are two ways to show changes over time. When 'Show cumulative' is selected, you will see street-network sprawl measures calculated for all roads built up to a particular date.
When 'Show cumulative' is turned off, you can instead see the level of street-network sprawl just for roads built during a particular period.