Comparative study of quantitative identification methods for peri-urban areas based on a multi-indicator system

As peri-urbanisation becomes widespread, quantitative methods for identifying peri-urban areas (PUAs) are increasingly abundant. This study aims to quantitatively compare the differences in the results obtained from multiple PUA identification methods within the same study area and to analyse the spatial patterns of the PUAs. The Threshold Method, Breakpoint Clustering, and Multilayer Perceptron were chosen to compare the identification results of PUAs in Zhengzhou City, China. The results show that the Threshold method identified the most PUAs but with the lowest accuracy. The accuracy of the Breakpoint Clustering was slightly lower than that of the Multilayer Perceptron. Regarding spatial layout, these identification results all show that the PUAs in the northeastern plains of Zhengzhou are more numerous than in the southwestern mountainous regions. Moreover, PUAs can generally be categorised into ring-shaped, belt-shaped, and patch-shaped forms. The spatial evolution of PUAs is influenced by urban expansion, geographical factors, and urban planning, and it can also provide timely reflections on urban development dynamics. These findings can provide valuable references for future research in selecting PUA identification methods, promoting in-depth longitudinal studies and cross-regional research, and enhancing the attention given to PUAs in urban planning and policy-making.