of Land Surface Temperature (LST) is inspired, which is the temperature of the near surface area within specified limit, but it is entirely different from atmospheric temperature. The LST is a new emerging concept in the field of remote sensing and it plays a key role in establishing an inter-relation between NDVI and LST (Deng et al., 2018). The relationship between LST and NDVI ponders on the concept of surface temperature in cram-full areas (Yuan and Bauer 2007). From this point of view, the area can be delineated as a Heat Island as the core area of the city experiences relatively high temperature than the surrounding and rural areas. The domain of UHI can be easily detected using these two crucial indices. The urban area that is comparatively hotter than the surrounding area can be considered as a UHI (Tso 1996).
India is home of 1,210,193,422 people (Census of India, 2011) and having a population density about 382 persons/km2, which represent a mass of population pressure on less amount of land. As a developing country, India is bound to see increase in urban area or converting land use into boundless built-ups. India is facing force of population toward urban areas and converting land use into boundless built-ups. Since independence, the growth rate of urban population is gradually rising and recorded 17.46% as per Census of India, 2011. Kolkata is one of the renowned metropolitan cities having the population density of approximately 24,000 persons/km2 (Census of India, 2011), one of the highest in the world. The suburbs (Barasat, Barracpore, Kalyani, Kashba, Rajarhat, etc.) are having density of almost 9,000 persons/km2, which is increasing rapidly. Because Kolkata is having limited land, the suburbs are developing at faster pace than the core city from last few decenniums. Barasat city is adjacent to Kolkata; therefore, the branches of Kolkata city are expanding toward the outskirt areas at faster rate and that can be clearly estimated from the difference in 2001 and 2011 Census.
1.2 Study Area
Barasat city is in the northern outer periphery of Kolkata city, in West Bengal, India, facing problems of unplanned urbanization in a short span of time after getting declared as district head quarter town within the jurisdiction of Kolkata Metropolitan Development Authority (KMDA). It has a total area of 31.41 km2 and extends between 88°27’ E and 88°31’E longitude and between 22°40’58” N and 22°44’44”N latitude (Figure 1.1). There are 32 wards in Barasat municipality. The growth rate of population in this town is very high and approximates around 3.5% per year. As per the provisional reports of census of India, population of Barasat in 2011 is 283,443. Barasat has a population density of 9,023 persons/km2.
1.3 Datasets and Methodology
1.3.1 Datasets
The satellite images of Landsat 5 TM for the year 2001, Landsat 5 TM for the year 2011, and Landsat 8 OLI and TIRS for the year 2017 were obtained from USGS official website and processed for analysis (Table 1.1), and to quantify the changes due to urbanization. The datasets used for various analyses and for preparing different maps along with census data are listed in Table 1.1.
1.3.2 Methodology
Landsat images of different time are very helpful for the analysis of land use and land cover change pattern and to measure the increase in urban built-up area (Song et al., 2001). To meet the objectives of the study, the following procedures were done. Pre-processing is an essential step for removing the atmospheric noise and haze, which is there in the image due to atmospheric scattering of solar radiation due to atmospheric elements (Chander, Markham, and Helder 2009). Satellite images were classified using Maximum Likelihood classification algorithm because it gives better accuracy than other available techniques like box classifier, minimum distance to mean, etc., available in published literature (Lyon et al., 1998; Reis 2008; Patidar and Sankhla 2015).
Figure 1.1 Location map of Barasat municipality.
Table 1.1 List of datasets used for the study.
| Satellite/Sensor | Date | Source |
|---|---|---|
| Landsat 5 (TM) | January, 2001 | USGS |
| Landsat 5 (TM) | January, 2011 | USGS |
| Landsat 8 (OLI and TIRS) | January, 2017 | USGS |
| MOD11A1 | January: 2001, 2011, 2017 | USGS |
| Census | 2011 | Census of India |
| Barasat municipality boundary | 2014 | Barasat municipality |
The study area was classified into six classes inclusive of built-up area, agricultural fallow, bare land, water body, green space, and built up with green space. The main aim was to measure the increase in built-up area, which is an indicator of urbanization. Further, accuracy of the classified images was calculated, and confusion matrix generated to highlight the user accuracy, producer accuracy, and Kappa statistics thus obtained (Foody 2002; Berberoglu and Akin 2009).
The urban growth is a process of urbanization, which always follows a pattern of development. In urban areas, the pattern differs from core to periphery region. In this study, two different types of pattern had been observed, one was concentric, and another one was linear. The concentric circular pattern was found in the areas of tri-junction of roads or in the “Y” point where the development is very rapid and shows multiplier effect of growth. The linear pattern of development was observed from 2001 to 2017 along the sides of roads and railway lines (Figure 1.2), which is very common in this region. Hence, both the developmental patterns are simultaneously affecting the environment of the area significantly.
Figure 1.2 Road and railways network in Barasat municipality.
NDVI is a very popular vegetation index used to measure the biomass content of vegetation with respect to its spatial entity (Volcani, Karnieli, and Svoray 2005). Two different bands, NIR and Red of remote sensing data, are used for calculating the NDVI (Bhandari, Kumar, and Singh 2012; Yin et al., 2012). The formula for NDVI (Eq. 1.1) calculation is as follows:
Remote sensing helps in deriving LST, which is used in various studies related to local climatology, meteorology, and
