Abstract: Building density map (BDM) product derived from remotely sensed imagery over large areas is the vital data set for supporting studies of human settlement environment and land use planning. GHSL (global human settlement layer) is a mapping project for developing human settlement map product with remotely sensed data. It is sponsored by the Joint Research Center of European Commission. The BDM is an important component of GHSL. Currently, the BDM of GHSL has been validated over Europe and America. However, the shapes of buildings and the landscape patterns of urban areas in East Asia, especially in China, are significantly different from those in the EU and US, and the validation of BDM over Asia is vital for further applications of the GHSL products. This study takes large area individual building footprint data sets over 5 typical mega cities (Shanghai, Xi'an, Changchun, Kunming and Urumqi) as ground truth through the pixel aggregation and the neighboring points searching and location matching, and the ground truth map of the building density is produced as the validation data set. With regression analysis, the method for BDM assessment is explored by calculating accuracy indicators over large metro-areas in China. The results show that the GHSL building density products of built-up areas reflect the densities of buildings in China at lower resolutions, but at higher resolutions they overestimate the densities in high-value areas. This study provides a basis for research and development of built-up area density products in China.

Key words: GHSL(global human settlement layer), built-up area, individual building footprint data, validation