基于网络分析的沈阳城市公园可达性和服务

Accessibility and service of Shenyang's urban parks by network analysis

城市公园是城市生态系统中主要的自然景观元素,发挥着重要的生态、经济、和社会效益。随着人们生活水平的提高,城市公园的休闲游憩功能倍受关注。以沈阳为例,基于GIS的网络分析法,结合道路和人口分布分析了沈阳及其各行政区城市公园的可达性和服务状况。结果显示:(1)网络分析法较缓冲区法更能准确地评价城市公园的可达性,两个服务评价指标(服务面积比和服务人口比)较传统的统计指标更能准确地反映城市公园的服务情况;(2)通过网络分析,研究区仅有19.47%的面积和43.41%的市民能够在15min内步行到达公园,沈阳城市公园数量不足且空间分布不均匀;(3)市区城市公园分布和服务情况好于郊区。沈河区、和平区和皇姑区城市公园可达性最好,东陵区、铁西区和大东区次之,于洪区和浑南新区可达性最差。基于GIS的网络分析法能够准确评价城市公园可达性,并可用于城市其它服务设施(学校、超市、医疗机构等)的可达性研究。研究获得了沈阳城市公园空间分布和服务状况的准确资料,为沈阳城市公园的空间布局优化提供参考。

Urban parks are one of the main natural components of an urban ecosystem, bringing great ecological, economic, and social benefits and playing an important role in ecosystem sustainability. The recreational functions of urban parks typically receive increasing concern as citizens＇ living standards increase. Residents are concerned about not only the quantity and quality of urban parks provided by the government, but also whether they can reach and enjoy urban parks conveniently. Can current urban parks satisfy the demand of citizens in a city and is the spatial distribution of parks reasonable？ How can the spatial distribution of urban parks in a city be optimized for maximum benefits？ Research on these questions is a prerequisite to planning and managing urban parks reasonably. In the past, answers to these questions were mainly acquired by questionnaire or statistical indices. However, both of these methods are deficient when evaluating the spatial distribution and service of urban parks, leading to increased attention to the issue of accessibility. The methods commonly used to evaluate accessibility （simple buffering, minimum distance, gravity model, and cost weighted distance） also have shortcomings, because they cannot measure the distance between urban parks and leisure users realistically. Network analysis solves this problem by measuring the distance of actual routes followed by leisure users. To test the usefulness of network analysis when evaluating urban park accessibility and to acquire comprehensive information about the current status of accessibility and service of Shenyang＇s urban parks, we studied the accessibility and service of urban parks in Shenyang and its eight districts based on road and population distribution data using Network Analyst model in ArcGIS 9.2. The results showed that： （ 1 ） The method of GIS-based network analysis is more precise than the simple buffering method when calculating urban park accessibility, and two service indicators （service area ratio and service population ratio） are better than the conventional statistical indicators used to quantify service status of urban parks. （2） Using network analysis, only 19.47% of the study area and 43.41% of the citizens are served based on the criterion that an urban park has a service radius of 900 meters （ 15 minutes walk ）. Shenyang＇s urban parks are inadequate in quantity and distributed uneven spatially. （3） The spatial distribution of Shenyang＇s urban parks and their service in the downtown area was better than that in the suburbs. Urban park accessibility was highest in Shenhe, Heping, and Huanggu Districts, while that in Dongling, Tiexi, and Dadong Districts was in middle place. Urban parks provision and accessibility was the most inadequate and problematic in Yuhong and Hunnan Districts. Our case study of the accessibility and service of Shenyang＇s urban parks indicated that the method of GIS-based network analysis evaluates the accessibility of urban parks exactly, and it can also be used to quantify the provision of and access to a range of urban services （schools, supermarkets, and medical institutions ）. What＇s more, the knowledge acquired about the accessibility and service of Shenyang＇s urban parks provided precise information useful for optimizing their spatial distribution.