Night light analysis: an alternative approach to measure urban Concentration

Abstract

The urban areas exhibit complex characteristics, difficult to control and map using conventional methods. The availability of a wide range of tools and techniques help in addressing the issue. The nighttime light data is one such technique employed to study the urban concentration, which is a freely available and reliable source of information depicting the night light on the surface of the globe. This thesis questions the significance of the night light data in urban studies. For the purpose, Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) nighttime light imageries of Kochi region for the years 1992, 2002 and 2012 are used. This thesis aims to analyse the importance of night time lights in studying the urban concentration and to study the significance of the night time activities in Kochi Region. It explores the applications of nighttime light imageries in studying the urban character based on the night light intensity. Out of various applications of the night light data, the study concentrates on the settlement and the activity analysis of the region. The nightlight intensity is used to analyse the magnitude and depth of the urban area. The sprawl of the area and the intensification of activities are studied using the Vegetation Adjusted Normalized Urban Index (VANUI) and it shows that the nighttime light data can be used as a proxy for the urban growth and activity analysis. The changing intensities also represent the land use change in the region. The night economy of the region is assessed to understand the on-ground activities at night. The night time economy is the reason for the night lights in the region. The Night Light Economy Index (NLEI) is calculated to find the economy representation of the night light data and is correlated to the GDP data. The results show a positive correlation between the datasets. The study demonstrates the applicability of the nighttime light data in studying the urban concentration. The night time light data is presently not used in urban planning. But the data proves to be of much help in urban studies. This research proposes the inclusion of night time light data in assessing the urban growth, market mapping and identification of informal sector.