Delineating urban hinterland boundaries in the Pearl River Delta: An approach integrating toponym co-occurrence with field strength model

Urban development requires the support of its surrounding areas. Accurate identification of urban hinterlands can help to scientifically evaluate strength and potential of urban development. The field strength model is regarded as an effective way to identify hinterlands, but the revision of friction coefficient has still not reached a consensus. With the application of big data in urban planning, it is possible to improve the field strength model. Toponym co-occurrence data, as a timely data source directly obtained from the Internet, can be used to reflect the spatiotemporal changes in urban connections, and provide an approach to quantifying the friction coefficient for the division of urban hinterlands. In this study, a new approach was developed by integrating toponym co-occurrence and improved field strength model. We considered the Pearl River Delta urban agglomeration as a case and identified the urban hinterland of each city. The results showed that the friction coefficient among cities fluctuated within a range of 1.25-2.50, the urban hinterlands were no longer confined to their own administrative divisions, and there was fierce competition with other cities. In particular, the urban hinterland of Guangzhou was 3699 km(2) larger than its actual administrative area. In addition, the proposed approach was more reliable in urban hinterland identification compared with the traditional fixed friction coefficient method. This study provides an improved field strength model based on toponym co-occurrence, which can identify urban hinterlands more accurately and objectively as well as promote the application of big data in urban planning.