基于GIS医疗设施空间可达性的研究——以大连市为例

基于可达性相关理论,以GIS网络和空间分析技术为基础,运用改进的潜能模型和两步移动搜寻法,对大连市各社区人口和医院进行叠加分析,将标准化的可达性数值进行插值处理,使之空间可视化,探究了大连市中山区、西岗区、沙河口区人口和二级以上医院空间分布现状,并对大连市医疗可达性进行了评价。结果显示:大连市医疗设施北部集中,总体分布不均。西岗区医疗可达性总体状况良好;中山区人口分布密集区,医疗可达性较好;沙河口区可达性较差,亟待提高。两步移动搜索法能更有效反应区域医疗可达性的空间分异。     

一种北京城区避难场所可达性评价方法

针对传统两步移动搜寻法应用于避难场所可达性研究中存在的中心供给、统一阈值及无距离衰减的问题,提出了"入口供给、分段阈值、高斯距离衰减"的优化方案。入口供给更符合人类的认知规律,分段阈值则充分考虑了避难场所的面积因素,高斯距离衰减符合可达性随距离递减的规律。改良两步移动搜寻法能够较好地揭示城市应急避难场所与人口相互作用的规律。基于ArcGIS平台,将改良两步移动搜寻法应用于北京城区应急避难场所的可达性研究,获得更加真实、可靠的评价结果,展现了改良两步移动搜寻法在公共服务空间可达性评价方面的重要作用。     

北京城区就医可达性评价及空间特征分析

以GIS网络和空间分析技术为基础,运用两步移动搜寻法对北京市城六区医疗服务的可达性进行了研究;综合比较了地面交通和轨道交通两种出行方式下的就医可达性结果,并对空间分布特征进行了分析,为相关部门设施规划和资源分配提供了重要依据。分析结果表明,北京城区就医可达性分布不均衡,呈从中心向外降低的圈层结构。     

基于交通网络的综合性医院可达性分析——以武汉市主城区为例

综合性医院是城市居民就医的重要场所,是现代医疗服务体系的重要组成部分。本文基于平峰、高峰两种时段的交通网络,利用高斯两步移动搜寻法和空间插值法对武汉市主城区进行了可达性分析。结果表明:1)两种时段的可达性一般及以上占比均较高,但平峰时分布更加均衡,高峰时极化特征明显;2)社区的可达性等级在空间上分异显著,呈现出连续的圈层式分布;3)不同区县之间分异特征明显,一般平均可达性更高的区县,其可达性波动更小,反之亦然。总之,本文为城市综合性医院可达性理论的深入、系统研究提供了一种新思路,对基于可达性的综合性医院空间布局优化具有重要的现实意义。     

利用网络泛地图资源评价15 min生活圈医疗服务可达性: 以上海市为例

现阶段中国投入大量资源用于基层医疗卫生服务能力建设,以15 min医疗圈为目标建设了卫生室、医保点等多种基层医疗保障设施,评价其可达性有助于设施的合理规划和优化调整。充分利用在线地图、人口热力图、路径规划服务、等时圈范围服务等泛地图资源,在基于胡弗模型的两步移动搜索法(Huff-based two-step floating catchment area method, Huff 2SFCA)的基础上,从出行能力差异、人口昼夜分布的角度进行改进,形成15 min核酸采样圈评价框架。以中国上海市为例分析15 min生活圈医疗设施可达性,结果显示: (1)研究区域内除宝山和浦东外的各行政区,15 min核酸采样圈的面积覆盖率和人口覆盖率均在90%以上,其中虹口、静安的可达性最高。(2)受通勤人群职住分离的影响,常住人口较多的地区在白天容易出现可达性过高的情况,且可达性在夜间降低,相反,产业聚集的地区夜间可达性明显升高。(3)外围的浦东、宝山等开发区呈现出可达性两极分化的特点,发展完善的居住板块可达性偏高,发展中的新产业园区可达性偏低;老城区的可达性分布相对更加均衡,且更能满足老年人群和职场人群的采样需求。分析结果反映出目前的采样点空间布局考虑了人群的出行行为,能满足大部分居民在居住地和工作地就近采样的需求。对于可达性过高和过低的区域,可根据人口分布的昼夜变化优化采样点资源配置。     

GIS与Voronoi多边形在医疗服务设施地理可达性分析中的应用

地理可达性是研究评价各种服务设施布局及其服务域的重要指标之一,空间距离、交通便捷性、出行成本等是可达性测度的重要因子。由于医疗设施等公共设施通常以服务的公平性和覆盖性为目标,因此可定义居民点到最邻近医院的距离为地理可达性的测度。在此基础上,作者提出了基于GIS与Voronoi多边形的地理可达性计算方法。这一方法不仅将地理可达性分析中的空间点对之间的距离计算简化为空间查询,方便了GIS应用,而且计算的Voronoi多边形在本质上就是最邻近意义上医院的服务域,即服务域内各居民点到该医院的距离就是最邻近距离。此外结合人口分布等属性数据,还可深入分析各医院的服务承载力,本方法为医疗设施等公共服务设施的规划决策提供了重要的工具。     

基于住宅小区尺度的城市基层医疗点可达性分析

推动基层医疗点在城市中的合理配置,对城市医疗体系建设有重要的意义.以住宅小区为研究单位,基于武汉市主城区的住宅小区和基层医疗点大数据,利用地理信息系统(Geographic Information System,GIS)网络分析技术和改进的两步移动搜索算法,从城市的不同环区尺度研究城市基层医疗卫生服务中心的可达性与完备性,为加强城市基层医疗卫生服务体系建设提供建议.结果表明:改进的两步移动搜索法较充分地考虑了距离衰减的影响,网络分析技术较合理反映了城市街区的可达性;不同环区基层医疗服务存在不均衡发展,一、二、三环区最近就医车行时间分别是平均17、14、15min;可达性指数空间差异显著,总体上主城区北部区域基层医疗服务可达性较低.为提高基层医疗服务的公益性,可以考虑在社区卫生服务中心覆盖不到的地区适当增设社区卫生服务站.     

基于改进的两步移动搜寻法的贫困区小学教育资源空间可达性分析——以重庆市黔江区为例

针对贫困区基础教育资源分布中出现的教育资源空间配置不合理等问题,以连片特困区一一武陵山片区的重庆市黔江区为例,以自然村尺度进行测算,重点研究并解决了贫困区教育资源空间布局现状的评估技术,以及两步移动搜寻法在农村贫困山区的关键技术改进和实现,并从供给和需求角度出发评价了教育资源的空间可达性。结果表明两步移动搜寻法适用于评估贫困山区教育资源的空间配置状况和分布情况;研究区教育可达性较高的地区不及需求总数的30％,分布在地形相对平坦,海拔较低的地区,服务范围内的学校多为中心校和实验小学,师资和占地面积优势大,但整体可达性并不理想。为相关部门有效配置教育资源,提出了“跑教”提升师资力量和恢复原有教学点等合理化建议。     

天津市市内六区基础教育资源空间可达性评价

教育资源空间可达性评价与研究可客观反映地区教育教学资源的空间分布状况,为教育资源空间布局的合理配置和优化提供科学依据。选择天津市市内六区为研究区,以街道为统计单元,利用两步移动搜索法对研究区内各街道的入学(小学和中学)可达性进行测算,分析了天津市市内六区基础教育资源空间分布特点。结果表明,天津市市内六区入学可达性在空间上存在显著差异,呈现以中心向四周逐渐降低的趋势;高可达性主要集中在中心地区街道,基础教育资源过剩地区和稀缺地区呈两极分化的格局;且与街道人口的空间分布不匹配。     

深圳市休闲设施轨道交通可达性的空间分异特征

轨道交通日益成为各大城市组织空间布局与社会生活的工具,提高休闲设施轨道交通可达性对于提高居民生活质量、促进设施公平共享具有重要作用.本研究以深圳市为例,运用改进的两步移动搜索法,分析了市级休闲设施轨道交通可达性的空间格局,计算了不同时间阈值下基于轨道交通的休闲设施服务人口与覆盖空间的分异.研究表明,休闲设施轨道交通可达性呈现非均衡结构,高休闲服务轨道交通可达性的区域存在阴影区,不同行政区内的休闲设施在吸引人群和服务范围等方面存在显著差异.研究就促进轨道交通与休闲设施在宏观、微观、人口与空间等方面的协同提出政策建议.     

Spatial and temporal variations of spatial population accessibility to public hospitals: a case study of rural–urban comparison

Quantification and assessment of nationwide population access to health-care services is a critical undertaking for improving population health and optimizing the performance of national health systems. Rural–urban unbalance of population access to health-care services is widely involved in most of the nations. This unbalance is also potentially affected by varied weather and road conditions. This study investigates the rural and urban performances of public health system by quantifying the spatiotemporal variations of accessibility and assessing the impacts of potential factors. Australian health-care system is used as a case study for the rural–urban comparison of population accessibility. A nationwide travel time-based modified kernel density two-step floating catchment area (MKD2SFCA) model is utilized to compute accessibility of travel time within 30, 60, 120, and 240 min to all public hospitals, hospitals that provide emergency care, and hospitals that provide surgery service, respectively. Results show that accessibility is varied both temporally and spatially, and the rural–urban unbalance is distinct for different types of hospitals. In Australia, from the perspective of spatial distributions of health-care resources, spatial accessibility to all public hospitals in remote and very remote areas is not lower (and may even higher) than that in major cities, but the accessibility to hospitals that provide emergency and surgery services is much higher in major cities than other areas. From the angle of temporal variation of accessibility to public hospitals, reduction of traffic speed is 1.00–3.57% due to precipitation and heavy rain, but it leads to 18–23% and 31–50% of reduction of accessibility in hot-spot and cold-spot regions, respectively, and the impact is severe in New South Wales, Queensland, and Northern Territory during wet seasons. Spatiotemporal analysis for the variations of accessibility can provide quantitative and accurate evidence for geographically local and dynamic strategies of allocation decision-making of medical resources and optimizing health-care systems both locally and nationally.     

Mapping the spatial disparities in urban health care services using taxi trajectories data

The understanding of spatial inequality in health care services is critical for reasonable policy‐making and management. In this study, we present a novel approach to analyze the demand–supply of health care services using taxi data. Taxi data provide observations of individual travel activities, and hence can be used to characterize the actual demand–supply of health care services. We apply the proposed approach in Guangzhou, China to carry out a case study. The results show the spatial disparities in health care service access. About 21.05% of the total population has high hospital accessibility, while the remaining 78.95% has relatively low hospital accessibility (i.e., roughly an “80/20” distribution). It is found that 6.29% of the population lives in high‐density suburban communities but has relatively low hospital accessibility. Most of the hospitals serve a population that is compatible with their capacity. One hospital is found to have a small capacity but to serve a large population, while two hospitals have relatively high capacities but serve small populations. These findings can help improve our understanding of spatial inequalities in public service provision, and may also provide useful information to address the health care problems of an aging population in contemporary, rapidly urbanizing China.     

改进G2SFCA的深圳市室内应急避难场所空间可达性研究

以深圳市为研究区，在考虑距离衰减效应的重力型两步移动搜索法（gravity two-step floating catchment area method，G2SFCA）基础上，引入Huff模型，并考虑需求点位置要素及地形要素，分别从供给点竞争、需求点定位、路网距离优化三方面对G2SFCA进行改进，并采用改进的G2SFCA对深圳市室内应急避难场所空间可达性进行研究。实验结果表明，改进的G2SFCA不仅能很好地揭示深圳市各社区室内应急避难场所的空间可达性，而且也能有效反映避难场所可达性与人口密度分布的空间匹配规律，较其他模型更符合现实情况；已建成室内应急避难场所数量、容纳人口及空间可达性的统计与分析结果真实、可靠，相关结论可为深圳市未来的防灾工作以及室内应急避难场所的空间规划与建设提供参考。     

Measuring differential access to facilities between population groups using spatial Lorenz curves and related indices

Access to certain types of facilities can promote health and well‐being. When population and facilities are not uniformly distributed across the landscape, inequities in accessibility may occur. Current research into GIS‐based accessibility measures has focused primarily on spatial inequities between different geographic locations but not directly on differences in accessibility between subgroups of the population. The research presented here develops a new method for measuring differential accessibility to facilities between various segments of the population. The method extends concepts and techniques in spatial point pattern analysis that account for the spatial structure of demand and its relationship to supply. In this approach, the traditional Lorenz curve and its associated indices, the Gini coefficient and the dissimilarity index, which are used to measure inequality, are recast in spatial terms for measuring differences in accessibility between population subgroups. An analysis of spatial accessibility to grocery stores in Akron, OH illustrates the value of the spatial Lorenz curve and its associated indices compared to other methods.     

公共医疗卫生服务的空间可达性研究——以广州市海珠区为例

本文以第5次人口普查以及医疗卫生机构相关数据为基础,运用空间相互作用理论和模型,得到广州市海珠区各街区的公共医疗卫生服务可达性空间分布,并详细分析了医院等级系数对可达性指数的影响,为医疗卫生事业的发展规划提供辅助决策支持。     

河南省高速交通网通达性时空特征及演化规律

针对河南省高速公路建设对城市通达性影响问题,该文通过定义时间阈值,设计了基于人口加权时间距离倒数的通达性指数,在4个时间断面上,研究河南省高速交通网络中通达性时空特征及演化规律,时间距离倒数有效减小了多路径时间距离对分析结果的数字影响。结果表明,随着河南高速交通网络的拓展,城市通达性水平得到了显著的提升,空间收敛显著,边缘城市的提升始终高于中心区域城市;高速公路通车里程增长率与通达性水平的改善存在非协调现象;城市通达性的空间聚集现象震荡走弱,聚集区域减少;城市通达性空间分布变化规律和城市化人口变化规律逐渐趋于协调。     

Polygon-to-Polygon Spatial Accessibility Using Different Aggregation Approaches: A Case Study of National Forests in the US Mountain West Region

Spatial accessibility is an enduring topic of spatial analysis that is intimately tied to issues of spatial representation and scale. A variety of methods to measure accessibility have been developed with most research focusing on metropolitan‐sized spatial extents using census‐defined aggregation units and relying on vector point representation to calculate Euclidean or network distances as key ingredients in measure formulations. Less research considers broader scales where both origin and destination points are treated as polygons. This research develops alternative gravity‐based measures of polygon‐to‐polygon accessibility for a case study of county‐level accessibility to national forests in the western US. Different methods of county and forest representation are implemented using census block centroids and a lattice approach for disaggregation and re‐aggregation. Other characteristics that are analyzed include origin‐destination linkage definitions, population weighting, and distance thresholds. Correlation analysis is used to assess relationships of alternative measures with a simple percentage measure and with each other. Low correlations would suggest that measures capture different aspects of accessibility that are related to their qualitative characteristics. Results show the alternative measures to be dissimilar from the percentage measure; however, high correlations among alternative measures suggest that there is little to differentiate certain disaggregated measures in spite of their richer qualitative interpretation.     

Spatial analysis of public health facilities in Riyadh Governorate,Saudi Arabia: a GIS-based study to assess geographic variations of service provision and accessibility

Much attention has been given to address public health policy in Saudi Arabia, particularly for the management, quality, and coverage issues. However, assessment of spatial patterns, distribution, and provision of public health services has been neglected. This paper analyzes the availability and accessibility of public health facilities across Riyadh Governorate, Saudi Arabia at the subnational level. Spatial and attribute data of public health facilities potentially have been analyzed using GIS to produce accurate measure of accessibility. The spatial pattern of service distribution was examined using average nearest neighbor. Distances from demand points (populations) to providers (facilities) were calculated for each district using near analysis. In addition, the ratios of public health facility to population were calculated to identify underserved and overserved areas. The findings clearly indicate that the spatial pattern of the distribution of public health facilities was significantly clustered (p value < 0.001) with Z-score of ?10.9. Several districts within the central parts of the governorate were identified as having a higher density of facilities, while most of districts that are located in the marginal parts exhibit very low density of health facilities. Overall, there was a considerable variation in the average distance from district centroids to health facilities. Substantially, less than half of the population (45.4%) living in 61 districts has access to public health facility within less than 1-km distance. In contrast, the greatest increase in distances was observed for 6% of population living in 38 districts. People that live in such districts need to travel long distances for public health care. The output of this analysis can assist policy-makers and authorities of Riyadh Governorate in planning public health delivery.     

Accessibility Futures

This study uses accessibility as a performance measure to evaluate a matrix of future land use and network scenarios for planning purposes. The concept of accessibility dates to the 1950s, but this type of application to transportation planning is new. Previous research has established the coevolution of transportation and land use, demonstrated the dependence of accessibility on both, and made the case for the use of accessibility measures as a planning tool. This study builds off of these findings by demonstrating the use of accessibility‐based performance measures in the Twin Cities Metropolitan Area. This choice of performance measure also allows for transit and highway networks to be compared side‐by‐side. For roadway modeling, zone‐to‐zone travel time matrix was computed using stochastic user equilibrium (SUE) assignment with travel time feedback to trip distribution. A database of schedules was used on the transit networks to assign transit routes. This travel time data was joined with the land use data from each scenario to obtain the employment, population, and labor accessibility from each traffic analysis zone (TAZ) within specified time ranges. Tables of person‐weighted accessibility were computed for 20 minutes with zone population as the weight for employment accessibility and zone employment as the weight for population and labor accessibility. Maps of accessibility by zone were produced to show the spatial distribution of accessibility across the region. The results show that a scenario where population and employment growth are concentrated in the center of the metropolitan area would produce the highest accessibility no matter which transportation network changes are made. However, another scenario which concentrates population growth in the center of the metropolitan area and shifts employment growth to the periphery consistently outperforms the scenario representing the projected 2030 land use without any growth management strategy.