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Urbanisation refers to the physical growth of urban region with the increase in the population due to either migration or amalgamation of peri-urban areas into cities. India, with 31.5% (377 million) urban population as per 2011 census, has been experiencing the global trend of increasing urbanisation. Urbanisation process involves changes in land uses and enhanced consumption of energy, which contribute significantly to the global warming. This necessitates developing effective urban planning strategies with the regular monitoring of landscape dynamics. Availability of temporal data of the earth's surface acquired through space borne sensors helps in mapping and monitoring landscape. Spatial metrics aid in quantifying the urban structure and patterns of urban growth. In this context, the current research reports of urban growth (urbanization and urban sprawl) in Ahmedabad, based on the temporal land use dynamics considering four decades remote sensing data with gradient analysis and spatial metrics. Urban land use dynamics, in terms of both patterns and quantities, were studied using Shannon Entropy index and select spatial metrics for the study area with 10 km buffer (from administrative boundary). This provided insights into the pattern of urban development and its complexity. Results indicate that Ahmedabad city has rapidly grown from 3.2 % to 14.58 % in the period from 1975 to 2010. Spatial metrics highlight that the core area of the city (which is the core financial area) has grown into a compact single urban class, whereas the outskirts have dispersed urban patches. This analysis helps the regional planners and decision makers in advance visualisation of urban patterns for sustainable planning of the city with basic amenities and infrastructure. [ABSTRACT FROM AUTHOR]

Abstract: Urbanisation is a dynamic complex phenomenon involving large scale changes in the land uses at local levels. Analyses of changes in land uses in urban environments provide a historical perspective of land use and give an opportunity to assess the spatial patterns, correlation, trends, rate and impacts of the change, which would help in better regional planning and good governance of the region. Main objective of this research is to quantify the urban dynamics using temporal remote sensing data with the help of well-established landscape metrics. Bangalore being one of the rapidly urbanising landscapes in India has been chosen for this investigation. Complex process of urban sprawl was modelled using spatio temporal analysis. Land use analyses show 584% growth in built-up area during the last four decades with the decline of vegetation by 66% and water bodies by 74%. Analyses of the temporal data reveals an increase in urban built up area of 342.83% (during 1973–1992), 129.56% (during 1992–1999), 106.7% (1999–2002), 114.51% (2002–2006) and 126.19% from 2006 to 2010. The Study area was divided into four zones and each zone is further divided into 17 concentric circles of 1km incrementing radius to understand the patterns and extent of the urbanisation at local levels. The urban density gradient illustrates radial pattern of urbanisation for the period 1973–2010. Bangalore grew radially from 1973 to 2010 indicating that the urbanisation is intensifying from the central core and has reached the periphery of the Greater Bangalore. Shannon''s entropy, alpha and beta population densities were computed to understand the level of urbanisation at local levels. Shannon''s entropy values of recent time confirms dispersed haphazard urban growth in the city, particularly in the outskirts of the city. This also illustrates the extent of influence of drivers of urbanisation in various directions. Landscape metrics provided in depth knowledge about the sprawl. Principal component analysis helped in prioritizing the metrics for detailed analyses. The results clearly indicates that whole landscape is aggregating to a large patch in 2010 as compared to earlier years which was dominated by several small patches. The large scale conversion of small patches to large single patch can be seen from 2006 to 2010. In the year 2010 patches are maximally aggregated indicating that the city is becoming more compact and more urbanised in recent years. Bangalore was the most sought after destination for its climatic condition and the availability of various facilities (land availability, economy, political factors) compared to other cities. The growth into a single urban patch can be attributed to rapid urbanisation coupled with the industrialisation. Monitoring of growth through landscape metrics helps to maintain and manage the natural resources. [Copyright &y& Elsevier]

The authors reflect on the major implications of the unplanned rapid urbanization of Bengaluru, India as of 2016. Topics include loss of natural resources, encroachment of lakes for construction of illegal buildings, large-scale fish mortality due to contamination and irresponsible water management and floods arising from wetland conversion for residential and commercial purposes. Other topics include decline in groundwater table and increase of carbon footprint.