A constraint-based approach for identifying the urban–rural fringe of polycentric cities using multi-sourced data

Studies on urban–rural fringes, which represent regions facing various urbanization problems caused by rapid expansion, have steadily increased in recent years. However, persist the quantitative delimitation of such regions. Based characteristics abrupt urbanization-level changes fringe areas, we propose a constraint-based method this study to detect fringes cities with spatial polycentric structure ‘Main center–Subcenter’ based data from multiple sources. We used proposed approach delimitate areas Jiangyin and Zhangjiagang identify their urban main center subcenter pre-defined city master plans, towns, rural hinterlands. Comparison identified results different single indices, detection center, kernel density estimation, constraint revealed that patch Shannon’s diversity index were higher smaller centers This suggests landscape delimitated is more fragmented, diverse, complicated, thereby performing better. significant for future analysis, planning, management.