Researchers at the Aerospace Information Research Institute, Chinese Academy of Sciences, have developed a novel methodology approach for assessing urban sustainability using data from the SDGSAT-1 satellite. Their study, published in Remote Sensing of Environment（https://doi.org/10.1016/j.rse.2025.114886）, , leverages demonstrates that high-resolution (10 m) Glimmer Imager observations to can revealprovide a detailed patterns of characterization of human activity, population aggregation, and intercity connectivity in across China’s three major urban agglomerations: the Beijing–Tianjin–Hebei region, the Yangtze River Delta, and the Guangdong–Hong Kong–Macao Greater Bay Area.
“Our work shows that satellites like SDGSAT-1 can provide a powerful lens to understand the dynamics of urban growth and resource flow at an unprecedented spatial resolution,” said Prof. ZHANG Lu, lead author of the study.
The research introduces two innovative indicators—the City Activity Index (CAI) and the Population Activity Index (PAI)—to quantify urban development levels and population aggregation efficiency. In addition, a new approach was proposedthe team developed a new method to extract intercity connection intensity from Glimmer Imager data, enabling the construction ofconstructing an urban nighttime “light flow” network that visually depicts maps the spatial patterns of resource flows and connectivity among cities.
Results reveal distinct development patternsstriking differences across among the three urban agglomerations. The Beijing–Tianjin–Hebei and Yangtze River Delta regions exhibit pronounced characteristicsstrong patterns of shaped by functional zoning and provincial boundaries. SpecificallyFor example, the light flow network in the Beijing–Tianjin–Hebei region closely corresponds tomirrors the functional zoning layout outlined in the Beijing Urban Master Plan (2016–2035), while connections in the Yangtze River Delta cluster predominantly align along provincial lines. In contrast, the Guangdong–Hong Kong–Macao Greater Bay Area presents a more highly integrated and balanced network structure, with the highest strongest intercity connection intensity, reflecting stronger a more collaborative and balanced urban development modeldevelopment capacity. .
“This study Our findings highlights the unique capability of high-precision nighttime imagery of SDGSAT-1 to capture fine-scalesubtle but crucial urban development dynamics,” Prof. Zhang noted.. The findings enhance our understanding of spatial structure and resource flow in China’s major urban agglomerations and provide valuable data support for“This information can support smarter urban planning, infrastructure development, and governance, offering important implications forhelping cities move towards advancing sustainable and resilient growth in line with the United Nations Sustainable Development Goal 11.” The lead author is Professor Lu Zhang from the Aerospace Information Research Institute, Chinese Academy of Sciences.
By leveraging SDGSAT-1’s fine-scale observations, this study provides new insights into the spatial structure and resource flows of China’s mega-city regions, offering a valuable tool for policymakers and urban planners seeking to optimize development and connectivity.