DMSP/OLS night-time light imagery for urban population estimates in the Brazilian Amazon

This article analyses DMSP/OLS night-time imagery as an information source to detect human settlements and to estimate the urban population in the Amazon region. DMSP/OLS single orbits were used to generate a DMSP stable light mosaic for 2002, in which most of the urban settlements with a population higher than 5000 inhabitants were precisely identified. DMSP/OLS night-time mosaic images from 1995, 1999 and 2002 were integrated with the IBGE census data and the correlation between DMSP/OLS night-time light area and the urban population was compared. Coefficients of determination higher than 0.8 were obtained from the linear regression between DMSP/OLS night-time lights and urban population census data. Although the fieldwork showed that DMSP image data could only record urbanized settlements with more than 2.5 km of well-lit surface areas, the initial and final extension of the night-time light foci were actually precisely registered. Therefore, this paper identifies the potential of DMSP night-time light images for estimating urban population as well as the technical limitations of using such images as a means to monitor urban population dynamics annually in a region where data are scarce and the demographic dynamics are unique, as in the Brazilian Amazon.