Global spatial patterns between nighttime light intensity and urban building morphology

The comprehensive characterization of global urbanization requires consideration of both human activities and urban physical structures. Both human activities and urban physical structures exhibit regular self-similar patterns, yet the spatial patterns between the two at a global scale remain elusive. This study utilized NPP-VIIRS annual composite data and newly available world settlement footprint 3D data to investigate the global spatial relationships between nighttime light intensity and urban building morphological indicators across several spatial scales. Our results demonstrated that there is a weak association between nighttime light intensity and urban building morphology at the pixel level, as shown by a maximum correlation coefficient of approximately 0.4, but a strong correlation at the provincial/state level with a correlation coefficient over 0.8. Additionally, we performed an urban-rural gradient analysis to evaluate the spatial patterns between nighttime light intensity and urban building morphological indicators. The results indicated that the dominant urban-rural gradients for both nighttime light intensity and building morphologies follow a declining trend from urban centers to rural areas. Notably, spatial inconsistencies between nighttime light intensity and building morphology were found predominantly in Africa. Our findings also suggested that spatial patterns between nighttime light intensity and urban building morphology can be served as an indicator of urbanization, and thus can provide implications for facilitating solutions aimed at reducing income disparity and promoting sustainable urban development.