The delimitation of functional spatial units or functional territories is an important topic in regional science and economic geography since the empirical verification of many causal relationships is affected by the size and shape of these areas. Most of the literature on the delimitation of these functional territories is based on developed countries, usually using contemporary and updated information of commuting flows. Conversely, in developing countries the technical contributions have been incipient. This paper proposes a complementary step in the delimitation of functional territories, combining stable satellite night lights and commuting flows, with applications for Mexico, Colombia and Chile. This method leads to a more accurate definition of functional territories, especially in cases where official data for commuting flows are unreliable and/or outdated, as is the case of several developing and underdeveloped countries. We exploit important advances associated with the use of satellite images, and specifically, the use of night lights as a source of information for the delimitation of metropolitan areas and urban settlements.
