Introduction

Landscape refers to all the visible features of an area of land such as the physical elements of landforms, human elements including land uses, buildings and structures, and water bodies (rivers, lakes and the sea). Land cover is the physical material at the surface of the earth and broadly refers to the region under vegetation and non-vegetation.  The human use of land involving the management and modification of natural environment or wilderness into built environment is referred as land use. Urbanization is the most dramatic form of irreversible land transformation (Gao et al., 2004), affecting landscape’s traditional integrity. It is a process in which an increasing proportion of an entire population lives in cities and the suburbs of cities. It brings the changes in the employment structure from small industries and agriculture to big industries. Urban areas account for 78% of greenhouse gases contributing significantly to global climate changes (Grimm et al., 2000).

Urbanization involves both social and physical transformation of landscapes, is a powerful, often irreversible and highly visible anthropogenic force (Shu-Li Huanga et al., 2009). Natural ecosystems and also human systems are getting affected due to growing urbanisation at all geographic scales (Herold et al., 2005). The rapid and often uncontrolled growth of the urbanising cities brings about numerous changes in the structure and functioning of landscape (Solon, 2009). Urban sprawl, a consequence of socioeconomic development under certain circumstances, has increasingly become a major issue facing many metropolitan areas (Ji, et al., 2006). Bangalore is one among the fastest urbanising cities in Asia, undergoing redevelopment for economic purposes and is witnessing tremendous pressure on the infrastructure, civic amenities, public services, etc. The growing migrant population, increasing number of Information Technology and Bio-Technology  (IT & BT) firms, and real estate projects are demanding more resources within the city, forcing it to expand both horizontally and vertically leading to serious infrastructure problems including scarcity of food, informal settlements, environmental pollutions, destruction of ecological structures, unemployment etc. The unprecedented growth and urban sprawl are often unnoticed by the planners, as they are unable to visualise this type of growth patterns. Since patterns are fundamental to many of the spatial-temporal relationships that we seek to discover, it is important to understand the factors and trend that influence the growth of the urbanising landscape. Therefore, characterising and understanding the changing patterns of urban growth is critical, given that urbanisation continues to be one of the major global environmental changes in foreseeable future (Rashed, 2008).

Drastic changes in the landscape composition alter the functional ability of cities (Frank, 1999) affecting the regional climate (Orville et al., 2000) and hydrology apart from inducing frequent disasters like floods, etc. (Ramachandra and Kumar, 2008). Urbanizations need to be planned taking into account all components of the landscape with a location specific advance plan.  Policy decisions of industrialisation or setting up of commercial complexes would lead to an increase in human population.  Economic, social, political etc. factors have a greater influence in the growth of Urbanization. Unplanned urbanization leading to sprawl brings the destruction of habitats, loss of agricultural land with serious impact on the ecology. Urban sprawl is also referred as irresponsible, and often poorly planned development that destroys green space, increases traffic, contributes to air pollution, leads to congestion with crowding and does not contribute significantly to revenue, a major concern. This drives the changes in urban patterns and most often the sprawl regions are devoid of basic amenities such as treated water supply, sanitation, electricity, etc. The urbanization and consequent sprawl are apparent in many regions (Vitousek et al., 1997; Antrop, 2000; Seto and Fragkias, 2005; Jantz et al., 2005; Martinuzzi et al., 2007), which necessitates planned development (Epstein et al., 2002; The Regionalist, 1997; Sierra Club, 1998). This phenomenon has been investigated in the developed countries (Batty et al., 1999; Torrens and Alberti, 2000; Barnes et al., 2001, Hurd et al., 2001; Epstein et al., 2002) and in developing countries (Yeh and Li, 2001; Cheng and Masser, 2003; Jothimani, 1997 and Lata et al., 2001; Sudhira et al.., 2003). Built-up area has been used as the parameter for quantifying urban sprawl (Torrens and Alberti, 2000; Barnes et al., 2001; Epstein et al., 2002; Fang et al., 2004). In this context, the nature and growth of urbanization is to be understood for effective planning considering the temporal aspects of  urban dynamics.

Urban planners and land resource managers require information regarding the changes of land use for an effective city planning. The land use master plans of each city are important for guiding their future urban expansion (Hai Minh Pham et al., 2011). To know the land use changes and urban expansions temporal Remote sensing data provides very useful information. Spatial data acquired remotely through space-borne sensors at regular intervals provide powerful tools for analysing urban land use changes and have been widely used in detecting and monitoring land cover changes (Pellikka et al., 2004; Seto and Kaufmann, 2003; Weber and Puissant, 2003). Remote sensing data (RS) along with geographic information systems (GIS) enable land planners, managers, and ecologists to display and quantify changes in landscape structure that result from disturbances (Turner and Carpenter, 1998).

Spatial metrics are used to understand the spatial heterogeneity at a specific scale and resolution (Herold et al., 2002).  The combined use of remote sensing and spatial metrics will lead to new level of insights to changes in the landscape (Herold et al., 2005). Better city planning at local level requires understanding of  the spatio-temporal aspects of landscapes. A spatiotemporal landscape metrics analysis across buffer zones is an improvement over using only urban growth rates  for comprehensive understanding of the shapes and trajectories of urban expansion (Seto and Fragkias, 2005). Landscape-level metrics have been developed to examine and provide meaningful ways of measuring landscape characteristics (O’Neill et al., 1988; McGarigal and Marks, 1995; Gustafson, 1998; Hargis et al., 1998; Jaeger, 2000).  These spatial metrics concentrate landscape information, and reflect the structural composition and spatial configuration of landscape features (Moquan SHA and Guangjin TIAN, 2010). In order to quantify the spatiotemporal dynamics with changes in landscape pattern and to describe the regularity of urbanization process, landscape metrics have been used (Wu, et al, 2000; Jenerette, et al, 2001; Grimm, et al, 2000). This communication is based on the analyses the urban sprawl and changes in landscape using spatio-temporal tools - GIS and RS along with spatial metrics and gradient analysis. The Objective of this study is 1) spatio temporal analysis of land use at local levels 2) computation of landscape metrics to understand the urban dynamics and 3) identify the agents of urbanization and urban sprawl at local levels.