Understanding Urban Cooling of Blue–Green Infrastructure: A Review of Spatial Data and Sustainable Planning Optimization Methods for Mitigating Urban Heat Islands

Many studies in the literature have assessed the blue–green infrastructure (BGI) characteristics that influence its cooling potential for sustainable urban development. Common assessment methods include satellite remote sensing, numerical simulations, and field measurements, each defining different cooling efficiency indicators. This methodological diversity creates uncertainties in optimizing BGI management. To address this, a literature review was conducted using Google Scholar, Web of Science, and Scopus, examining how the BGI cools urban space, which spatial data and methods are most effective, which methodological differences may affect the results, and what the current research gaps and innovative future directions are. The results suggest that remote sensing is ideal for large-scale BGI comparisons, numerical simulations for local development scenarios, and field measurements for assessing conditions closest to residents. Maximum BGI cooling intensity averages show 4 °C from remote sensing, 3 °C from field measurements, and 2 °C from numerical simulations. Differences in conclusions may arise from differences in the data resolution, model scale, BGI delineation method, and cooling range calculation. The key BGI characteristics include object size, vegetation fraction, foliage density, and spatial connectivity. Future research should prioritize the integration of the different methods, BGI shape complexity effectiveness assessment, and effects of urban morphology on evaluating BGI characteristics’ effectiveness, and explore digital twin technology for BGI management optimization. This study integrates key information on BGI’s cooling capabilities, serving as a useful resource for both practitioners and researchers to support resilient city development.