Study Areas and Data

This study has been carried out focusing on the current mega cities - New Delhi, Mumbai (Bombay), and Kolkata (Calcutta) and Hyderabad. Mumbai (with a population of 16.37 million) is located at the west coast in the state Maharashtra. Delhi (with 13.78 million population) located in northern India on the flood plains of river Yamuna, has the status as the National Capital Territory and has. Kolkata (13.22 million population)_, the capital of the Indian state West Bengal, is located in eastern India in the Ganges Delta in a flat surrounding at the Hooghly River and Hyderabad city (6.42 million population) is situated in the heart of the Deccan Plateau at an average height of 540 m. Spatial growth of these cities has been analysed using temporal remote sensing data.

The RS data were obtained from the Global Land Cover Facility (GLCF – http://www.landcover.org/), and from the U.S. Geological Survey (USGS) and NASA’s Landsat mission website. Beginning October 2008, the archived data of the Landsat missions were made available freely by USGS. Accordingly, the cloud free data corresponding to1990s and 2010 were downloaded and processed. Since 1982 the Thematic Mapper (TM) has operated with 30 meter geometric resolution and seven spectral bands. Since 1999 the Enhanced Thematic Mapper (ETM) has operated with an additional panchromatic band and 15 meter geometric resolution. Having continuous, constant spectral bandwidths guarantees the comparability of the different sensors. With its field of view of 185 km the satellite is able to survey the large metropolitan areas of the study sites. Measurement of areal coverage and spatial distribution are both needed to describe the morphology of an urban area adequately (Schweitzer et al. 1998).