Abstract
The urban polycentric structure is connected to the economy and enormously impacts socioeconomic development and policies. Unlike traffic data and big geographic data, remote sensing data have shown an accessible way to measure urban spatial interaction. However, most existing studies only focused on the interaction among cities rather than within cities. Meanwhile, the urban spatial interaction, which should be directional, was always expressed as an undirected graph. Therefore, this article developed a network-based radiation model using nighttime light remote sensing data and mapped a directed interaction network (inward and outward direction) among urban centers. Taking the region within the outer ring of Shanghai as an example, the taxi trajectory data were adopted to validate the result with the <i>R</i><sup>2</sup> of 0.61. We discovered that: the urban polycentric interaction network is dumbbell-shaped with an east-west development corridor crossing the main center and connecting two main urban center clusters. The in-strength and out-strength interaction of each urban center have a similar distribution. The urban centers with higher in-strength and out-strength are mainly concentrated toward the main center, especially in the east-west direction. At the urban center level, the total inward interaction is slightly higher than the total outward interaction of most urban centers. Spatially, an unbalanced distribution was found. In summary, our proposed method effectively indicates the urban polycentric interaction and is applicable to other regions since it requires no arbitrary parameters and the input data (e.g., nighttime light data) is readily available.
Highlights
W ITH the accelerating pace of urbanization, many changes happened in cities for good or for bad, such as the rural–urban migration, the population growth, and the spatiotemporal dynamics of urban expansion [1,2,3]
We successfully developed an effective way to measure the urban polycentric interaction based on the NPP-VIIRS Nighttime light data (NTL) composite data
Polycentric communication within urban areas is becoming more common and studying the urban polycentric interaction within cities can help the future development of cities
Summary
W ITH the accelerating pace of urbanization, many changes happened in cities for good or for bad, such as the rural–urban migration, the population growth, and the spatiotemporal dynamics of urban expansion [1,2,3]. In the process of urbanization, the spatial distribution and interaction among cities evolve and transform [4]. The urban spatial interaction has gradually changed from single mobility to an integrated mobility containing many urban factors, such as commuting, commerce, intra-day mobility and call patterns, et al [5,6]. The urban spatial interaction among cities can measure and reflect the intensity of the relationship between cities. A growing body of literature focuses on regional spatial interaction and attempts to measure and evaluate their structure and characteristics [7,8,9]. How to measure the urban spatial interaction becomes a crucial challenge for future studies
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