City-scale data are estimated using a combination of existing national and regional statistics, scaling factors, and city-specific contextual data—such as population, building stock data, or business patterns.
The data are estimated using standardized and transparent methodologies - the Global Protocol for Cities (GPC) guidelines describe the use of national statistics and scaling factors to estimate community-scale data.
National and regional statistics, and city-specific contextual data are compiled from authoritative data sources of the specific country.