Spatio-Temporal Assessment of Built-Up Expansion in Ghaziabad District, India Using the Normalized Difference Built-up Index (NDBI)

Abstract

Background: Urbanisation in developing countries has considerably changed land surfaces, including through urban expansion and its effects on natural landscapes. Aims: The present study investigates the spatial distribution and temporal variation of built-up regions.  Study Design: The Normalized Difference Built-up Index was used to map and quantify the spatial distribution and temporal variation of built-up spaces. Place and Duration of Study: The NDBI was used to analyse spatio-temporal changes in urban expansion in Ghaziabad district, Uttar Pradesh, India, using multi-temporal Landsat imagery from 2013, 2018, and 2023. Methodology: The Normalized Difference Built-up Index was used to assess built-up expansion in Ghaziabad district. To create NDBI maps and examine built-up growth trends, the satellite imagery was pre-processed and analysed using geospatial techniques. Results: The findings show that substantial urbanisation occurred over the study period, especially in the vicinity of the main transport corridors and fast-growing urban and peri-urban centres. Urbanisation was associated with increased infrastructure development and land-use change, leading to declines in open space and cultivated land. The built-up space increased from 639.12 km² in 2013 to 678.70 km² in 2018 and further to 683.96 km² in 2023. Correspondingly, the number of built-up pixels increased from 710,134 in 2013 to 754,106 in 2018 and 759,961 in 2023. The total built-up space increased by 44.84 km² (7.02%) during 2013–2023, with an increase of 39.57 km² (6.19%) between 2013 and 2018 and 5.27 km² (0.78%) between 2018 and 2023. Conclusion: The results offer important insights into the dynamics and intensity of urban expansion and may inform sustainable urban development, land management, and environmental protection in fast-growing areas.