Perinthalmanna in context: Street-network sprawl trends

The chart above shows SNDi trends for new street additions (left panel) and the entire network (right panel), with Perinthalmanna plotted against Kerala and India. The SNDi of new construction in Perinthalmanna was at its lowest in 1976-1990, compared to Kerala which was at its lowest in 1976-1990 and India which followed a zig-zag trend with an overall increase. Most recently, Perinthalmanna's incremental SNDi rose from 5.96 to 7.63 between 1991-2005 and 2006-2020. In terms of the aggregate network, Perinthalmanna ranked 41st out of 48 cities in Kerala and 1697th out of 1868 in India as of 2020.

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

What about similarly populated cities?

• Natore, Bangladesh
• Zhaishang, China
• Miyazaki, Japan
• Pukou, China
• Duyun, China
• Shorsh, Iraq

In new street additions, Perinthalmanna built increasingly connected streets from 1975 through 1976-1990, then shifted to more disconnected patterns, while Natore built increasingly disconnected streets from 1975 through 1991-2005, then improved and Pukou built increasingly disconnected streets from 1975 through 1976-1990, then improved. For the full network, Perinthalmanna became more connected from 1975 through 1976-1990, then grew more sprawly from 1976-1990 onwards, while Natore became progressively more disconnected and Pukou grew more disconnected from 1975 through 1976-1990, then improved. Perinthalmanna and Natore have been converging in their street-network character since 1975.