Sicily: region in Italy
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 Sicily, Italy on the sprawlmap
Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Sicily as of 2014, the overall level of street-network sprawl is 2.61, which is in the 40th to 60th percentile of disconnectedness.
Trends in street network construction: The SNDis of street construction for the respective time periods are 1.86, 3.85, 4.53 and 4.57. In each period, new street development in Sicily steadily grows more disconnected than in the last. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 1.99 points, but between 1991-2000 and 2001-2014, it rose by just 0.04.
Quantity of street network construction: The street network in Sicily spans a total of 43035 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 1.86, 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 1.86, 2.47, 2.54 and 2.61. Overall, the SNDi of the aggregate street network has risen: the street network in Sicily has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.61 points, but between 1991-2000 and 2001-2014, it rose by just 0.07.
The level of street-network sprawl in new development in Sicily rose steadily. To get a sense of how street development has changed in Sicily, we can consider three of its most populous cities: Palermo, Catania and Messina. Out of the three cities, Palermo and Messina do not follow the same trend as the region. The level of street-network sprawl in new development in Palermo followed a zig-zag trend. The level of street-network sprawl in new development in Messina peaked in 1991-2000.
How do development practices in Sicily fare in comparison to others in Italy? Most recently in 2001-2014, street construction in Sicily was the 7th-most disconnected out of the 17 regions in Italy. Its position in the ranks since 1975 has risen; relative to other regions in Italy, street construction in Sicily has become more disconnected. Sicily ranked 16th in 1975, 10th in 1976-1990, 8th in 1991-2000 and 7th in 2001-2014.
As of 2014, the city with the most disconnected street network in Sicily is Catania with an SNDi of 2.7, which is in the 40th to 60th percentile of disconnectedness. Conversely, the most connected city is Trapani with an SNDi of 0.77, which is relatively well-connected. See trends for these cities: Trapani, Catania
The level of street-network sprawl in the aggregate network in Sicily rose steadily. To get a sense of how the aggregate street network has changed in Sicily, we can consider three of its most populous cities: Palermo, Catania and Messina. Disconnectivity in the most populous cities in Sicily follow the same region trend.
To date, Sicily is the 16th-most disconnected out of the 17 regions in Italy. Its position in the ranks since 1975 has not changed. Sicily ranked 16th in 1975, 16th in 1976-1990, 16th in 1991-2000 and 16th in 2001-2014.