Accurate identification of high-quality development level of resource-based city economy is not only conducive to the transformation of urban economic structure, but also conducive to the sustainable utilization of resources. Based on speed, efficiency and production theory, this paper divides the high-quality economic development stages of resource-based cities. The panel smooth transformation (PSTR) model is used to identify the high-quality economic development level of 30 coal cities in China from 2003 to 2020, and further analyzes the transformation rules. The results show that: First, the high-quality economic development level of resource-based cities is highly correlated with the intensity of resource industry, and has obvious stage characteristics. Second, from 2003 to 2011, the number of coal cities at the high and medium level of high-quality economic decelopment increased from 12 to 19, and that at the low level decreased from 18 to 11. This indicates that most coal cities improved the high-quality economic development level. Third, the high-quality economic development of 11 coal cities has realized the single-stage transition, only Wuhai city has achieved the transition from low to high level, and the remaining 18 coal cities are in stagnation. Further, the driving mechanism analysis shows that industrial structure upgrading is an important factor to promote the transition of high-quality economic development stage in coal cities. It indicates that the improvement of high-quality economic development level of coal cities is a long-term process, which requires continuous promotion of economic transformation.

According to the comprehensive efficiency of multiple input factors in the evaluation of tourism resource efficiency, which cannot separate the output efficiency of a single input factor, in the perspective of tourism resource transformation efficiency, the resource transformation efficiency, its spatial differentiation characteristics and the interaction influence mechanism of the 81 typical red tourist attractions were evaluated by using the modified DEA model, spatial autocorrelation method and geographical detector model in Hunan province in 2020. The results showed that: (1) The transformation efficiency of red tourism resources in Hunan was 0.332, and it presented a spatial pattern of high in the east and low in the west. (2) Red tourism resources production efficiency and transformation efficiency of local space correlation from east to west gradually exhibited a decreasing trend. On this basis, the efficiency types of red tourism resources can be divided into five types, that is, the coordinated efficiency of production of red tourism resources, the comprehensive quality and efficiency improvement of red tourism industry, the transformation and upgrading of red tourism resources, the comprehensive production capacity improvement of red tourism resources, and the comprehensive efficiency cultivation of red tourism resources. (3) Three endogenous ability elements, namely, product innovation ability, human capital quality and tourism market scale, were the leading factors of red tourism resources in Hunan. Product innovation ability and science and technology information level, human capital quality and tourism market scale, human capital quality and economic development level were the internal and external factors leading to the spatial differentiation. The results enriched the theory of tourism efficiency research and can provide scientific reference for regulating the efficiency of red tourism resources to provide feasible development approaches and promoting the high-quality transformation and development of red tourism economy in Hunan province.

Resource-based cities are the cities that take the exploitation and processing of natural resources (minerals, forests, etc.) in the region as the leading industries (including prefecture-level cities, regions and other prefecture-level administrative regions, and county-level cities, counties and other county-level administrative units). They are important guarantees for the protection and utilization of energy resources in China and promote the sustainable development of the national economy. However, in the process of development, resource-based cities are facing problems such as resource depletion, environmental degradation, and lack of endogenous power of transformation. Therefore, promoting resource-based cities transformation and development is a key measure to accelerate the construction of ecological civilization and build a new development pattern in the new era. This study takes 19 resource-declining cities (prefecture-level cities) as the research object, and constructs an influencing factor index system of tourism transformation and development of resource-based cities, including four dimensions of ecological environment, resource environment, economic environment and cultural environment. On this basis, using the method of qualitative comparative analysis of fuzzy sets, this paper makes necessity analysis of single variable and multivariate path configuration analysis to explore the influencing factors and driving types of tourism transformation and development of resource-based cities. It is found that: (1) Environmental regulation is a single necessary condition for the transformation and development of tourism in resource-declining cities. Under the guidance of the government, effective environmental regulation can reduce the damage to the ecological environment caused by the economic growth of resource-declining cities, and then provide a good ecological environment for tourism development. (2) There are four driving types in the transformation and development of tourism in resource-declining cities: economic development driven, environment-culture driven, environment-energy-culture driven and environment-economy-culture driven models. On this basis, by comparing the core conditions of various types, we can further find that the environment and culture play a more important role in the process of tourism transformation. (3) There are four driving types leading to the transformation and development of non-tourism: environment-economy inhibition, environment-economy-culture inhibition, cultural endowment inhibition and economy-culture inhibition. It can be seen that economic development, cultural endowment and environment are the key to restricting the tourism development of resource-declining cities. From the perspective of configuration, this study combs the influencing factors and action mechanism in the process of tourism transformation in resource-declining cities, and further analyzes the driving types of "tourism transformation development" and "non-tourism transformation development". The research results not only enrich the relevant academic achievements of the transformation and development of resource-based cities, but also provide academic support and theoretical reference for their practical development.