Affiliation: | 1. College of Tourism and Environment Sciences, Shaanxi Normal University, Xi'an Shaanxi 710062, China; 2. Northwest Land and Resources Research Center, Shaanxi Normal University, Xi'an Shaanxi 710062, China 3. College of Tourism and Environment Sciences, Shaanxi Normal University, Xi'an Shaanxi 710062, China; Northwest Land and Resources Research Center, Shaanxi Normal University, Xi'an Shaanxi 710062, China |