Rapid and unplanned urbanization in the least developed districts of Bangladesh: a case study from Jamalpur using geospatial techniques

Sustainable urban development is a key compoment in the United Nation’s Sustainable Development Goals. Monitoring urbanization is critical for planners, governments and non-governmental organizations, and scientists to design policies that maximize the use of natural resources and accommodate development while reducing environmental effects. This research aims to analyze how urbanization patterns have changed in the largely unknown least developed regions of Bangladesh. Multispectral satellite imageries over 30 years (1991 to 2021) were used to analyze the urbanization pattern of Jamapur district. Utilizing object-based image classification and on-field validation for seven Land Use and Land Cover classes, it was found that built-up area expanded by 748.92% during the past three decades while depleting bare soil (− 97.65%), deep waterbody (− 79.33%), shallow waterbody (− 8.46%), light vegetation (− 14.28%) and agricultural land (− 26.33%). Because of increased in built-ups, the land surface temperatures (LST) were also increased over the study period (the minimun recorded LST were 12.84 °C, 15.89 °C, 15.8 °C and 17 °C while the maximun LST were 17.93 °C, 23.7 °C, 23.79 °C and 26.73 °C for the year of 1991, 2001, 2013 and 2021 respectively). This study will act as a baseline for future studies It be insightful to urban planners and policymakers in developing countries regarding urban sustainability and minimizing urban risks and hazards in the least developed districts.