Using Smart Card Data of Metro Passengers to Unveil the Urban Spatial Structure: A Case Study of Xi’an, China

Table 2

The number of significant flows of each city center

Center type	Center	The number of significant flows
Residential center	Hangtiancheng center	12
	Yundonggongyuan center	6
	Fangzhicheng center	5
Employee center	Zhonglou center	20
	Xiaozhai center	14