Research on the delineation of urban growth boundary based on integration and “dual evaluation”: A case study of the Zhengzhou Metropolitan Area, China

Metropolitan areas, as core spatial vehicles driving socioeconomic development, urgently require their spatial governance to transition from “single-city” approaches to “regional coordination”. The Urban Growth Boundary (UGB), as a key measure for balancing economic development with ecological conservation and advancing sustainable development, urgently requires transcending the limitations of individual cities. It must prioritize regional coordination to meet the practical demands of metropolitan area integration.This study focused on the Zhengzhou Metropolitan Area (ZMA) in China, applying a comprehensive approach and the PLUS model for land use simulations and UGB delineation with integration and “dual evaluation”. The results showed that (1) The PLUS model based on integration and dual evaluation demonstrates high land use accuracy (Kappa: 0.92, overall: 96.2 %) and can be applied for UGB delineation at the metropolitan scale. (2) Simulations indicate that land use in the study area is trending toward a decrease in cropland, shrubland, and grassland, an increase in water and construction land, while forest coverage remains largely stable. (3) In different scenarios, the UGB in the study area expanded (with expansion rates ranging from 17.7 % to 21.8 %) and the connections between towns strengthened. (4) The spatial expansion of the controlled-scale boundary, baseline boundary, and buffer zone of the ZMA's urban growth control primarily exhibits a composite “block-and-belt” expansion pattern, covering areas of 13,105.04 km 2 , 11,915.02 km 2 , and 2766.94 km 2 respectively. The study offers a replicable approach for metropolitan land use management, advancing urban sustainability and providing a scientific foundation for spatial governance in ZMA. • Overcoming the limitations of defining UGB based on individual cities. • Introducing flow space theory to build an integrated, dual-evaluation land simulation. • Simulate UGB dynamics at the metropolitan level across various scenarios. • Balancing multiple objectives, providing a basis for land use and spatial governance.