Analysis of land use and land cover dynamics and drivers of urban expansion in and around Imphal city, India, using geospatial and random forest techniques

Imphal city and its surrounding regions have been experiencing a wide range of changes in land use and land cover (LULC) over recent years. However, there is a shortage of comprehensive studies that specifically examine the long-term dynamics in general and driving factors behind these changes in particular. This study provides a detailed analysis of LULC changes in Imphal city and its surrounding regions from 1991 to 2021, using advanced geospatial techniques to investigate underlying dynamics and driving factors behind urbanization. Multi-spectral datasets from Landsat 7 and 8 were utilized for four distinct time periods (1991, 2001, 2011, and 2021). The supervised classification method, employing the maximum likelihood classifier method, was used to generate the classified LULC maps in the ERDAS 2014. The classified images produced by this technique were evaluated for accuracy through matrix union using the statistical kappa coefficient and overall accuracy measures. Change detection for the periods 1991–2001, 2001–2011, and 2011–2021 was conducted using matrix union (intersection) to identify apparent changes in various LULC classes. The findings reveal a significant increase in built-up areas, expanding from 2440.35 hectares in 1991 to 8205.98 hectares in 2021, at an annual rate of 192.19 hectares/year. In contrast, agricultural lands decreased from 7484.13 hectares in 1991 to 3585.42 hectares in 2021, declining annually by 129.96 hectares/year. The study utilizes classified supervised images from various years, alongside seven independent spatial variables, to analyze urban growth and expansion using the method of random forests regression technique in Python, validated through receiver operating characteristic curve. Analysis of these seven variables, including distance to roads, proximity to the city centre, and infrastructure development, identifies them as primary drivers of urban expansion. The study concludes that rapid urbanization is significantly reshaping LULC dynamics, underscoring the urgent need for sustainable urban planning and management strategies.