P. Sutton et al., Census from Heaven: An estimate of the global human population using night-time satellite imagery, INT J REMOT, 22(16), 2001, pp. 3061-3076
Night-time satellite imagery provided by the Defense Meteorological Satelli
te Program's Operational Linescan System (DMSP OLS) is evaluated as a means
of estimating the population of all the cities of the world based on their
areal extent in the image. A global night-time image product was registere
d to a dataset of 2000 known city locations with known populations. A relat
ionship between areal extent and city population discovered by Tobler and N
ordbeck is identified on a nation by nation basis to estimate the populatio
n of the 22920 urban clusters that exist in the night-time satellite image.
The relationship between city population and city areal extent was derived
from 1597 city point locations with known population that landed in a 'lit
' area of the image. Due to conurbation, these 1597 cities resulted in only
1383 points of analysis for performing regression. When several cities fel
l into one 'lit' area their populations were summed. The results of this an
alysis allow for an estimate of the urban population of every nation of the
world. By using the known percent of population in urban areas for every n
ation a total national population was also estimated. The sum of these esti
mates is a total estimate of the global human population, which in this cas
e was 6.3 billion. This is fairly close to the generally accepted contempor
aneous (1997) estimate of the global population which stood at approximatel
y 5.9 billion.