Urbanization monitoring using big Earth Observation data for world heritage sites of China

World heritage is a precious treasure left to mankind by history. It is a treasure of all human civilization and has very important historical, artistic and scientific value. Protecting world cultural heritage is a prerequisite for protecting the inheritance of human culture, safeguarding the diversity and creativity of the world's culture, and promoting the development of mankind. However, the rapid urbanization process globally has changed the land cover/land use, transportation and environmental conditions in cities, and has caused some impacts and damages to the world heritage sites. Based on three global Earth Observation datasets including Global Human Settlement Layer (GHSL), global population grid products (Worldpop) and the global night-time light images (DMSP/OLS), this paper proposed an urbanization intensity index (UII) to dynamically monitor and quantitatively assess the intensity of urbanization around the world heritage sites. Large UII values represent high urbanization degrees in the study area, and vice versa. The rapid increase of UII indicated that great impacts might be caused by the urban development process on corresponding heritage sites. The assessment results showed that the mean value of UII at 10 world cultural heritage sites in China's urban areas increased from 0.35 in 2000 to 0.42 in 2015. The urbanization intensity index of the world cultural heritage sites can provide valuable datasets and scientific basis for the protection and development of world cultural heritage sites.