Songming in context: Street-network sprawl trends

Songming in context

1.82.73.64.5<19751976–19901991–20052006–2020SNDi of street additions
1.82.73.64.5<19751976–19901991–20052006–2020SNDi of entire street network
SongmingYunnan (Region)China (Country)

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Songming plotted against Yunnan and China. The SNDi of new construction in Songming peaked in 1976-1990, compared to Yunnan which followed a zig-zag trend with an overall increase and China which followed a zig-zag trend with an overall increase. Most recently, Songming's incremental SNDi fell from 2.66 to 1.97 between 1991-2005 and 2006-2020. In terms of the aggregate network, Songming ranked 20th out of 78 cities in Yunnan and 557th out of 1843 in China as of 2020.

New Street Additions (2006–2020)

SNDi value
1.97
Rank in China
234th of 1843
Rank in Yunnan
8th of 78

Entire Network (Aggregate)

SNDi value
2.47
Rank in China
557th of 1843
Rank in Yunnan
20th of 78

Rankings go from most connected to most disconnected — rank 1 is the most connected.

What about similarly populated cities?

22.533.5<19751976–19901991–20052006–2020SNDi of street additions
22.533.5<19751976–19901991–20052006–2020SNDi of entire street network
SongmingIzumoCherbourg-en-Cotentin

In new street additions, Songming built increasingly disconnected streets from 1975 through 1976-1990, then improved, while Izumo fluctuated in its street-construction patterns and Cherbourg-en-Cotentin built increasingly disconnected streets from 1975 through 1991-2005, then improved. Looking at the full network, Izumo and Cherbourg-en-Cotentin both became progressively more disconnected, while Songming grew more disconnected from 1975 through 1976-1990, then improved. Songming and Izumo have been converging in their street-network character since 1975.