2001年以来中国旅游景区时空格局演变与景区群形成
宁志中, 王婷, 杨雪春

Spatio-temporal evolution of tourist attractions and formation of their clusters in China since 2001
NING Zhizhong, WANG Ting, YANG Xuechun
图7 2016年旅游景区群核密度圈层结构特征
Fig. 7 The layer structure of kernel density of tourist attraction clusters of China in 2016