Evaluating Small-Scale Urban Regeneration Using Nighttime Lights and Sentinel-2: Evidence from Republic of Korea

Developing effective evaluation frameworks for urban regeneration in non-metropolitan areas is increasingly challenging, particularly for small-scale projects where conventional administrative indicators are often insufficient on their own. This study examines 46 regeneration projects in Republic of Korea and integrates nighttime lights (NTL), Sentinel-2 indices, and administrative statistics to identify how different project types produce observable changes. The results show that NTL is effective mainly in economy-based and central commercial area projects, where increases in radiance correspond to the expansion of commercial functions, higher business activity, and stronger evening economic operations. In contrast, NTL shows limited responsiveness in residential-support projects, reflecting the low baseline illumination and weak lighting elasticity of residential environments. For these areas, Sentinel-2 NDVI and NDBI provide clearer evidence of improvements, capturing localized changes in vegetation, built surfaces, and pedestrian environments that are not detectable through nighttime radiance. Comparative assessments indicate that most changes are concentrated within project boundaries, though external development projects occasionally influence spectral patterns in adjacent areas. These findings demonstrate that combining NTL and Sentinel-2 data offers a more context-sensitive approach to evaluating small-scale regeneration and highlights the importance of selecting indicators suited to specific project types. The study provides an empirical foundation for more adaptable, data-driven evaluation frameworks in non-metropolitan regeneration policy.