Objective  The evaluation of existing recreation service resources within the Great Wall National Cultural Parks and the optimization guidance strategy based on such evaluation are of notable significance and influence for protecting and inheriting cultural resources, maintaining the regional ecological environment, driving the development of tourism in the surrounding area, and providing theoretical support for the high-quality development of the Great Wall National Cultural Parks.

Methods  Based on the review of relevant literature, and the current status of the Great Wall National Cultural Park (Beijing section), the research area, this research constructs a recreation service evaluation system applicable to the Great Wall National Cultural Park (Beijing section), which involves fifteen indicators in five aspects. The research firstly conducts a comprehensive evaluation of recreation services in the research area based on multisource data and the ENVI 4.8 and ArcGIS 10.5 software, with the weighting vector being determined by the Delphi method and the entropy value method. Subsequently, the research analyzes the differences in distribution pattern of recreation services between different districts and towns, and explores the relationship between recreation services and existing attractions and nature reserves in terms of spatial distribution. Finally, the research proposes the guidelines for future construction and development to help the government and other construction entities understand the overall development status of the research area, and thus reasonably formulate optimized development strategies.

Results  1) The naturalness of recreation is affected by the distribution of water resources, which is identified as significantly higher in the eastern and central parts of the research area than in the western part. The culturality of recreation tends to gather into patches, with high-value areas being concentrated along the Great Wall, almost all located within the protected areas under control. The difference in recreation aesthetics between districts is small, with high-value areas being concentrated on the slope toward the residential gathering place and on both sides of the road. The spatial distribution of recreation convenience and of recreation comfort are correlated to a certain extent, with high-value areas being concentrated in the connections between the central urban area and the four key areas of Juyong Road, Huanghua Road, Gubeikou, and Malan Road. 2) The spatial distribution of recreation potential and that of recreation opportunities are correlated to some degree, with high-value areas mostly concentrated in Pinggu district and Huairou district, and low-value areas mostly concentrated in Mentougou district; the current development essentially relies on existing recreation resources, which is reasonable overall, but less reasonable locally. For example, Changping district is featured by low potential but overdevelopment. High-potential and high-opportunity areas are concentrated along the Great Wall and around densely populated towns; high-potential and low-opportunity areas are the fewest compared with the remaining three categories, mostly concentrated in the mountainous areas around high-potential and high-opportunity areas, with the most scattered spatial distribution; low-potential and high-opportunity areas are mostly located between high-potential and high-opportunity areas and towns; low-potential and low-opportunity areas are concentrated in mountainous areas far away from residential gathering places. 3) The spatial distribution characteristics of township recreation potential and recreation opportunity are similar, both showing the trend of high-level townships concentrated in the central and western part of the city, the most prominent in Huairou district and Pinggu district. However, the spatial distribution of high-potential townships is more concentrated in the central part, and that of high-opportunity townships is concentrated in the four key areas of Juyong Road, Huanghua Road, Gubeikou, and Malan Road. There are eleven townships with matching recreation potential and opportunity, and twelve townships with greater opportunity. 4) Of the existing attractions, 80% have high recreation opportunities, and the infrastructure construction around the attractions is relatively complete, but only 67.15% of the attractions are located in high-potential areas, indicating that the existing attractions have a low proportion of high-quality recreation resources, and there is a waste of recreation opportunities. Twenty-two nature reserves are mostly located in areas with low potential and opportunities, predominantly because the nature reserves are mainly for the protection of natural resources, limiting the amount of tourists' recreation. 5) According to the results of recreation service evaluation, the research proposes recreation service optimization strategies for the research area as a whole, and respectively for high-potential and high-opportunity areas, high-potential and low-opportunity areas, low-potential and high-opportunity areas, and low-potential and low-opportunity areas. Meanwhile, the research also proposes the guidelines for optimized development of the townships, attractions and nature reserves involved in the Great Wall National Cultural Park (Beijing section) from the perspective of resource integration and integrated development. By enriching the cultural indicators of and building a recreation service evaluation system applicable to the Great Wall National Cultural Park, the research comprehensively evaluates the recreation service potential and current development level of existing resources, and accordingly reveals the current status of recreation service in existing attractions, nature reserves and townships, thereby proposing optimized strategies, and providing a scientific basis for the development of recreation resources and the improvement of recreation service capacity in the research area.

Conclusion  According to the connotation and characteristics of national cultural parks, the research constructs a recreation service evaluation system applicable to the Great Wall National Cultural Park (Beijing section) based on the enrichment of cultural indicators to effectively evaluate the recreation service potential and current development level of existing resources, and reveal the current status of recreation services in existing attractions, nature reserves and towns, which can help the government and other construction entities understand the overall development status of the research area and reasonably formulate optimized development strategies.