GDP spatial differentiation in the perspective of urban functional zones

The current spatial analysis of urban GDP mainly focuses on macroscopic scales such as city and county level. The internal economic spatial differentiation characteristics of cities have not attracted enough attention. This study aims to fill this gap by exploring the issue of GDP spatial differentiation from the urban functional zone (UFZ) perspective. First, the road network was used to delineate urban units, and UFZs were identified using XGBoost classifier with multi-source data. Second, the distribution of the GDP was analyzed using the spatial autocorrelation model. Third, the correlation between UFZs and GDP was explored by the random forest algorithm. Results indicate that: (1) the UFZs were identified with an overall accuracy of 0.931, and the industrial and residential zones were the dominated functions in the study area; (2) the GDP gradually decayed from the center to the periphery in the study area and had significant spatial autocorrelation. (3) Among all the UFZs, the residential zones had the strongest correlation with the GDP. This study contributes to urban planning, construction, and coordinated regional development by providing replicable methods and ideas for adjusting and optimizing urban industrial structure.