The spatial distribution of nodes with underlying network for: (a) Taipei city; (b) Taichung city; (c) Kaohsiung city. DDPR ranks result with 0.5 hour transportation network for: (d) Taipei city; (e) Taichung city; (f) Kaohsiung city; and GPR ranks result for: (g) Taipei city; (h) Taichung city; (i) Kaohsiung city. The size of the nodal circle is proportional to the ranks of DDPR or GPR scores. The nodes with higher rankings are concentrated in the central area in Taipei City (d,g), in the southern inner area in Taichung City (e,h), and in the southern coastal area in Kaohsiung City (f,i). These higher-ranking nodes capture the locations of central business district (CBD) among the three cities. The lower ranking nodes are located in the outer rings of Taipei City. The northern Taichung, with lower rankings, is separated from the CBD by a river. In Kaohsiung City, the areas with lower rankings are concentrated in the northern underdeveloped regions. Data souce: Institute of Transportation, MOTC (Taiwan).