As agricultureis the mainstay of national economy, loss ofcultivated land becomes grave concern that cancontribute to the increase of landlessness and jeopardizingthe economy. Furthermore, food shortage couldbe acute in the coming years, and it would be a greathurdle for Bangladesh to meet up the rising fooddemand for its ever growing population.Dhaka, the capital of Bangladesh could be the bestillustration of human activities and associated environmentalchange. Dhaka is expanding apace, at anaverage rate of 4.24%/year and is projected to be thethird largest megacity in the world by the year 2020(World Bank 2007). The growth of the city is
phenomenal after independence (Chowdhury andFaruqui 1989) and highest among other cities inBangladesh due to its socio-economic and politicalimportance. The growth is mainly attributed to thelarge influx of rural to urban migration (Islam 1996).The population of Dhaka increased from 556,712 in1961 to the current more than 12 million (World Bank2007). Rapid urbanization on the other hand, led to the deterioration of city’s environment, particularlymounting flood risk potential (Dewan and Yamaguchi2007), severe environmental pollution (Karn andHarada 2001; Karim 1999; Azad and Kitada 1998),and spectacular growth of informal settlements (CUSet al. 2006; Islam 1996).Even though most of the developed countries arewell equipped and updated with detailed land use/cover information, lack of and/or restricted access togeospatial database persists in developing nations,predominantly in Bangladesh. Aerial photograph, forinstance, absolutely classified for public. For thirdworld countries, remote sensing proved its effectivenessfor spatial data updating