Analysis of the Spatio-Temporal Dynamic of Polycentric City Using Night-Time Light Remote Sensing Imagery

Due to urban population explosion and increasing demand of urban space, the spatial structure of urban built-up area has been transformed from mono-centric to polycentric, especially for intensively urbanized regions. In this study, we used global radiance calibrated DMSP-OLS night-time light data, integrated with Gaussian volume model and gravity model, to probe into the spatio-temporal dynamic of polycentric urban structures and the mutual influences among urban centers. Our results prove the effectiveness of the framework in extracting the urban extent and quantitatively describing the urban centers' features in terms of the intensity of human activity, morphology, trajectory and mutual influences. In addition to the drastic expansion urban centers, this framework reveals the dominant status as well as a strong attraction of the main center to the sub-centers. Our findings are expected to be beneficial for decision makers to evaluate the ongoing urban planning layout.