Quantifying the degree-of-freedom, degree-of-sprawl, and degree-of-goodness of urban growth from remote sensing data

Urban growth is a spatial and demographic process and refers to the increased importance of towns and cities as a concentration of population within a particular economy and society. Analysis of urban growth by using the historical and present data is an essentially performed operation in the urban geographic studies and for future planning. Urban growth can be mapped, measured and modelled by using remote sensing data and GIS techniques along with several statistical measures. In this study three temporal satellite images of 15 years interval (1975, 1990 and 2005) have been classified to determine the urban extent and growth of Kolkata-Howrah (West Bengal, India) in eight different directions within a circular region. Pearson's chi-square test and Shannon's entropy method have been applied to calculate the degree-of-freedom and degree-of-sprawl towards the analysis of urban growth. A new measure, degree-of-goodness, has also been proposed for the analysis of urban growth. The result shows that the city of Kolkata-Howrah has a high degree-of-freedom, high sprawl, and a negative goodness in urban growth. Apart from the derived results, this study also shows the potentials of remote sensing data and effectiveness of demonstrated/proposed models in urban geographic studies. (C) 2009 Elsevier Ltd. All rights reserved.