Demographic characteristics and changing land use pattern in Gangtok, Sikkim (1975–2011)

Gangtok, the capital and the largest town of the state of Sikkim lies at 27.33°N latitude and 88.62°E longitudes, located in the eastern Himalayan range at an elevation of 1, 650 m (5, 410 ft). It is among the fast growing town of Sikkim. Increase in population has led to drastic change in land use pattern especially conversion of green cover areas into built up area. During the decades of 1991 and 2001, the population growth rate was only 17.30 percent, but the population of Gangtok town has increased to 100286 in 2011 from 29354 in 2001 which is around 241percent increase (census of India). The land use pattern of the town has been categorized in six categories i.e. residential, commercial, public and semi-public, transportation, industrial and recreational. In post-merger period, public and semi area has also been expanded from merely 0.55 percent in 1975 to 23 percent in 2014. In the last three decades, the highest growth rate has been seen in the industrial sector, which shows a growth rate of 363.41percent from 1985 to 1995. There has been 6percent and 16.40percent increase in the transport and recreational sectors respectively during the time span of 1975 to 2006. This paper focuses on demographic growth and land use changes of Gangtok since 1971 using integration of remote sensing with GIS technology to identify various types of changing land use pattern. In this paper LANDSAT-TM (Bands 1, 2, 3, 4, 5, 6 and 7, imagery year of 2001 and 2011, Path and Row =139/41) data has been used for land use/Land cover mapping. The Supervised Classification Method has been applied for delineating the study area into different land use land cover classes by using ERDAS 13.0 and Arc GIS 10.1 was used for mapping Population Density and Urban Growth.