## 3 Spatiotemporal Differentiation of Coupling Coordination Degree between Tourism and Urbanization
### Spatial Distribution of Coupling Coordination Degree between Tourism and Urbanization
#### 3.2.1 Spatial Pattern Distribution of Tourism and Urbanization Development Level  
From the perspective of spatial distribution, tourism development in the Yangtze River Delta Urban Agglomeration presents a spatial pattern of orderly changes (Figure 3). In 2008, the tourism development of Shanghai was at a high level, while those of Nanjing, Suzhou, Hangzhou, and Ningbo were at an upper-medium level, forming an overall spatial structure of \"one pole and multiple cores\". In 2013, Shanghai was still at a high level; Nanjing, Suzhou, and Hangzhou were at an upper-medium level; Ningbo changed from an upper-medium level to a lower-medium level; Wuhu jumped from a low level to a lower-medium level.  
In 2018, Shanghai remained in the leading position; Huzhou and Taizhou rose to a medium from a low level; Nanjing and Suzhou shifted from the upper-medium level to the medium level. These findings demonstrate that the level of tourism development has stepped up; the gap between high-quality regions and low-quality regions is large; and the  
Figure 3: Spatial temporal pattern of Yangtze River Delta tourism industry in 2008 (**a**), 2013 (**b**), and 2018 (**c**).  
grade characteristics are significant. Some mature tourism cities do not maintain their original industrial development advantages in the process of tourism development, and some even show a relative regression. These findings indicate that the development of tourism in these cities has not kept pace with the change of the diversified demands of mass tourism and timely adjustment, and that the effective supply of tourism is insufficient. In general, the development level of tourism essentially matches the regional economic development.  
The spatial distribution of urbanization development in the Yangtze River Delta Urban Agglomeration is unbalanced, presenting a relatively stable spatial pattern (Figure 4). From 2008 to 2018, China's urbanization process improved rapidly, and the level of urbanization significantly increased. In 2008, Shanghai and Nanjing were rated as high-level urbanization areas. In 2013, Suzhou, Wuxi, and Tongling rose from an upper-medium level to a high level, and Changzhou, Zhenjiang, Jiaxing, and Ningbo from a medium level to an upper-medium level.  
In 2018, Yangzhou, Taizhou, and Nantong advanced from a lower-medium to a medium level. Overall, the urbanization level of each city presents the spatial characteristics of agglomeration and diffusion, expanding from the main cities in the coastal areas to the surrounding cities and forming the agglomeration area with a high urbanization level in the coastal urban agglomeration. Shanghai exhibits unique geographical conditions and resource endowment and has a strong ability to gather elements, thereby maximizing the polarization and siphon effect. Yancheng in northern Jiangsu Province and Xuancheng, Anqing, and Chizhou in Anhui Province have always been at a low level, caused by their lack of industrial support, innovation ability, and low level of openness, to some extent reflecting the \"Matthew effect\" of the quality of urbanization development.  
Tongling in central-southem Anhui Province experienced a process of urbanization development from an upper-medium level to a high level and then regressed to a medium level. This curve shows that resource-based cities tend to excessively depend on resources, leading to an imbalance of the proportion of industrial structure. Subsequently, ignoring the imperative for environmental protection slows down or even regresses economic development.