Analysis of impervious surface expansion trends during urbanization in Long An ward using Sentinel-2 imagery from 2016 to 2025

Abstract

The urbanization process has led to a significant increase in impervious surface area, reducing the natural water infiltration capacity. On the other hand, urbanization also serves as a driving force for socio-economic development. This study utilizes Sentinel-2 satellite imagery at three time points (2016, 2020, and 2025), combined with the Random Forest algorithm on the Google Earth Engine platform, to classify and map impervious surfaces and analyze urban expansion trends over time in Long An Ward. The results show that impervious surfaces have rapidly increased, from 5.76 km² in 2016 to 7.01 km² in 2020, reaching a peak of 10.46 km² in 2025. Notably, the trend of impervious surface expansion is mainly concentrated in the southeastern and northeastern areas of Long An Ward, as identified through the Urban Expansion Intensity Index (UEII). This approach provides an important data foundation for planning and supports sustainable urban management in the context of increasing urbanization.