城市绿地可达性与公平性评价

城市绿地是城市重要的绿色基础设施,是实现城市可持续发展的重要空间保障,具有重要的生态、社会文化功能.20世纪80年代以来,我国一直以城市人均(公共、公园)绿地面积、绿地率、绿化覆盖率等面积比率指标作为核心指标来指导城市绿地建设,缺乏具体引导城市绿地空间分布的指标,较少关注城市绿地服务功能的公平性问题.借助于GIS技术,构建了城市绿地社会功能评价的简明框架,尝试将表征城市绿地空间分布的可达性和公平性指标引入城市绿地的功能评价中,以体现城市建设"以人为本"、"社会公平"的理念,并以上海和青岛为实证,对新构建的系列指标进行了分析与检验.研究结果表明:(1)可达性和公平性系列指标导入城市绿地的功能评价中是可行的,能够有效的表征和测度城市绿地空间布局的合理性程度;(2)可达性和公平性指标使用时需要界定研究区范围、研究尺度,特别是数据精度,以利于研究区的纵向比较和城市间的横向比较.研究结果将丰富我国城市绿地评价的核心指标体系,亦可为城市规划者和建设者合理规划与布局城市绿地提供重要的依据和参考.

Accessibility and equity assessment on urban green space

Urban green space is the main part of urban green infrastructure, regarded as the important spatial basis for urban sustainable development, and can provide ecological, recreational and social-cultural functions. Since 1980s, the urban planners and policy-makers widely took the urban green space area per capita, public green space area per capita, urban park area per capita, the ratio of urban green space, and green space cover ratio, etc. as the key indexes to guide planning and management in China. However, only a few indexes reflecting the spatial allocation and structure of urban green space are used, and few policy-makers and planners pay attention to the spatial equity of urban green space service functions.Since the Reform and Open Policy were initiated in the 1980s, Chinese cities have been facing rapid urban sprawl, but most of the cities implemented green space planning in the 1990s. So, the number of patches and area of urban green space in Chinese cities could not satisfy the increasing demands of citizens. With socio-economic development, Chinese people and governments are paying much more attention to urban green space, and more and more citizens have the desire for contact with nature, and are willing to live close to urban green space. Consequently, governments plan to develop and optimize urban green space allocation to meet these demands. Quantification of accessibility and equity of urban green space is a prerequisite to assess them as a tool for decision-making in planning. However, GIS-based accessibility and equity analysis has not yet been used to evaluate the accessibility and equity of urban green space in China. Chinese planners have been unable to give spatial accessibility and equity of urban green space a comprehensive evaluation, so their plans based on their experience could be arbitrary.In this paper, supported by GIS, the new study frame for assessing the social function of urban green space is established, within which, the accessibility and equity indexes are used to analyze the rationality of the urban green space spatial structure, through a case study of Shanghai and Qingdao city, China. Results demonstrate that: (1) the accessibility and equity indexes are effective to appraise the structure of urban green space, and using the new study frame to guide the planning and management of urban green space is feasible; (2) when the indexes are used, the study area and scale, especially the data resolution need to be defined to compare the temporal data series in the study area or with the other cities. The new frame in this paper will enrich the key index system for assessing the urban green space in China, and can provide planners and policy-makers with important and valuable information that can be used in urban green space planning and assessment.