Global Human Settlement Layer, Degree of Urbanisation

Several new global agendas call for the collection of harmonised indicators for cities, urban and rural areas. Because no harmonised method to delineate these areas is available, indicators rely on national definitions, which vary considerably and thus limit international comparability. This new method, called the Degree of Urbanisation, classifies the entire territory of a country along the urban-rural continuum. It combines population size and population density thresholds to capture the full settlement hierarchy. 1 km2 grid cells are classified based on population density, contiguity and population size. It classifies the entire territory of a country into three classes: cities, towns and semi-dense areas, rural areas. It has two extensions. The first extensions additional categories like suburban or peri-urban areas, dispersed rural areas, uninhabited areas etc. The second extension adds a commuting zone around each city to create a functional urban area or metropolitan area.
The GHS Urban Centre Database (GHS-UCDB) is another dataset of describes spatial entities called “urban centres” according to a set of multitemporal thematic attributes gathered from the GHSL sources integrated with other sources available in the open scientific domain. The Urban Centres are defined by specific cut-off values on resident population and built-up surface share in a 1x1 km uniform global grid. The input data is generated by the GHSL, and the operating parameters are set in the frame of the “degree of urbanisation” (DEGURBA) methodology.