Vigan in context: Street-network sprawl trends

Vigan in context

3.64.55.46.37.2<19751976–19901991–20052006–2020SNDi of street additions
3.64.55.46.37.2<19751976–19901991–20052006–2020SNDi of entire street network
ViganIlocos Sur (Region)Philippines (Country)

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Vigan plotted against Ilocos Sur and Philippines. The SNDi of new construction in Vigan peaked in 1991-2005, compared to Ilocos Sur which followed a zig-zag trend with an overall increase and Philippines which rose steadily. Most recently, Vigan's incremental SNDi fell from 5.73 to 5.43 between 1991-2005 and 2006-2020. In terms of the aggregate network, Vigan ranked 1st out of 1 cities in Ilocos Sur and 61st out of 114 in Philippines as of 2020.

New Street Additions (2006–2020)

SNDi value
5.43
Rank in Philippines
45th of 114
Rank in Ilocos Sur
1st of 1

Entire Network (Aggregate)

SNDi value
4.8
Rank in Philippines
61st of 114
Rank in Ilocos Sur
1st of 1

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

What about similarly populated cities?

23456<19751976–19901991–20052006–2020SNDi of street additions
23456<19751976–19901991–20052006–2020SNDi of entire street network
ViganChihuRong'an

In new street additions, Vigan built increasingly disconnected streets from 1975 through 1991-2005, then improved, while Chihu built increasingly disconnected streets over time and Rong'an fluctuated in its street-construction patterns. For the full network, Vigan and Chihu both became progressively more disconnected, while Rong'an fluctuated in connectivity.