Functional Urban Areas -Application of the concept on traditional longitudinal data for intra-and inter-city analysis

As the world becomes more urbanized, a deeper understanding of cities is increasingly valuable for achieving the United Nations' Sustainable Development Goal 11 (SDG 11). Official statistics contain important information for monitoring the social and economic sustainability of cities, but they do not follow a consistent definition of cities around the world. The United Nations has endorsed the use of Functional Urban Areas (FUA), defined based on global remote sensing data, as the standard delineation of cities worldwide. However, the FUA definition cannot be directly applied to official statistics, which are usually aggregated according to national administrative units. In order to improve internationally comparative urban research, this study provides a tool for matching the FUA definitions to countries' administrative geographies. The matching process identified 57% of all GHSL FUAs worldwide in the existing country-specific administrative geographies. The percentage of matched FUAs is generally higher in countries with more refined administrative units. The population of matched FUAs does not differ much from GHSL FUAs. Larger GHSL FUAs tend to be better matched than smaller GHSL FUAs. The analysis of eight FUAs in the Global South reveals significant inter-and intra-city differences in demographic behaviors and highlights the importance of these more realistic definitions of the spatial extent of cities, as compared to the administratively defined city territory, for accurate monitoring of cities. This research provides researchers and urban planners with useful tools to better analyze urbanization at the international level in order to plan sustainable urban development, maximize the potential of cities for human development, and monitor progress towards SDG 11 globally.