Abstract:

A metropolitan area, which plays a dominant role in the regional economic development, is defined as a composite of a densely populated urban core and its surrounding interlocking territories. It is essentially a unified labor market that is delimited by the commute flows between a principal city and the peripheral area in most of foreign countries. However, due to the absence of commuting census data in China, it is either too difficult to conduct delimitations based on the commuting linkage or the results could be completely different from those in foreign countries. We based our delimitation on commuting flows identified from mobile phone data, which records the users' spatio-temporal information while they communicate with the network via towers. First, we inferred the user's residence and workplace using two weeks of China Mobile's 2G mobile signaling data in 2014. Then, we delimited the boundary of Shanghai metropolitan area according to the foreign standards. Additionally, we proposed to utilize the recreational activity, also inferred from the mobile phone data, as an auxiliary standard to adjust the boundary. The conclusions can be drawn as follows: (1) In terms of commuting flows, the Shanghai metropolitan area covers the surrounding area of the central city, the Songjiang new town and the large industrial zones in the urban fringe, while in terms of recreational activity, it includes the surrounding area of the central city, the new towns of Songjiang, Jiading, Qingpu, the Huinan area, and the Changxing Island. Morphologically, the Shanghai metropolitan area is slightly longer in the east-west direction and narrower in the north-south direction. (2) The commuting and recreational connections can be combined to delimit a metropolitan area in China, while the former could be the primary indicator with the latter as the auxiliary. (3) Huge difference exists between the metropolitan area of Shanghai and the foreign ones. The foreign metropolitan areas usually have more expanded ranges covering surrounding jurisdictional zones, while the Shanghai metropolitan area mainly grows within its administrative boundary and is confined to a relatively small area around the central city.

Key words: metropolitan area, boundary delimitation, mobile phone signaling data, Shanghai