Different factors may determine the presence of human populations in a specific region, including historical
processes, accessibility, availability of natural resources, presence of urban facilities and infrastructure and
local physical characteristics, among others. The relative importance of each factor is also a fundamental
variable that may vary according to local conditions. As an example, the global population distribution model
proposed by Landscan used the following as indicator variables: land cover classes, distance to roads, slope
classes and the presence of night lights from the DMSP/OLS sensor (Badhuri et al. 2002).