Study area and data

Chennai is capital city of Tamilnadu state, India. It is located between two major rivers i.e. Coovum and Adayar and at the eastern coast - Coromandel Coast line also known popularly as “Gateway to South India”. Chennai is known as “Detroit of India” due to the presence of a wide array of automobile industries. Chennai has tropical wet and dry climate with temperatures ranging from 15°- 40°C. The jurisdiction of the Chennai (city) Corporation was expanded from 174 sq. km (2001) to 426 sq.km in 2011. Chennai Metropolitan Area (CMA) has an area of 1189 km²comprising Chennai city district and partially extending to two districts Kancheepuram and Tiruvallur. Chennai is presently fourth most populouscity in India with 4.68 million (2011), whereas CMA population shows an increase of 1.86 million considering 2001 and 2011 census. and socio-economic factors.

Hyderabad is a capital of Telangana state and Andhra Pradesh (after partition in 2014). The city is located along the banks of river Musi and surrounded by many lakes like Himayat Sagar, Hussain Sagar, etc. It has very old history since 1500’s under Nizam’s rule. Hyderabad is the largest contributor to the gross domestic product. With creation of special economic zones at Gachibowli, Pocharam, Manikonda etc. dedicated to have encouraged companies from across India and around the world to set up operations. Erstwhile Hyderabad urban development authority (HUDA) was expanded in 2008 to form Hyderabad metropolitan area (HMA) covering 7100 km² and population of 7.74 million (2011). HMA covers a total of 5 districts namely Hyderabad, Rangareddy, Medak, Mehaboobnagar and Nalgonda. Chennai and Hyderabad are at the verge of attaining “Mega city” status (urban agglomerations greater than10 million inhabitants), while India already has 3 mega cities namely Mumbai, Delhi and Kolkata (United Nations, 2012).
The geographical bounds of the two study cities are given in table 1.

Table 1: Geographical extents of Chennai and Hyderabad metropolitan area

3.1 Data acquisition

Temporal data of Landsat 5 (TM), Landsat 7 (ETM+) and Landsat 8 (OLI-TIRS) satellites were downloaded from the public archive of USGS Earth Explorer. IRS LISS-III data was procured from the National Remote Sensing Centre (NRSC) for the year 2012. A circular buffer zone of 10 km from an administrative boundary (centroid as central business district) as in figure 1 was considered to account for likely growth or sprawl at outskirts or peri-urban regions. Data used land cover and land use analyses and for transition rules are listed in table 2.

Figure 1: Location of Chennai and Hyderabad

Table 2: Data used for the analysis