A spatiotemporal analysis of metro-stop based accessibility to bus services in Shanghai,China

Ground-level bus offers flexible services with relatively inexpensive fares and high-level accessibility, thus is the dominant feeder mode for metro in the majority of metropolitan areas in China. Intermodal transfer between the metro and bus networks is therefore a crucial element in the successful operation of an integrated transit system. In this circumstance, a key challenge is lack of appropriate methodologies to evaluate the spatial–temporal disparities of intermodal transfers between metro and bus. To address this issue, this research aims to promote an existing two-step floating catchment area (2SFCA) model by incorporating the temporal variability of service supply, demand, and travel time to provide a more realistic estimation of accessibility using smart card data and automatic vehicle location data. The proposed methodology was applied in a case study of the metropolitan area of Shanghai in the specific context of metro-stop based accessibility to bus services. The results of the case study show that the daily fluctuations in output metro-to-bus transfer accessibility values are highly sensitive to temporal dynamics of transfer time, service supply, and demand. It is hoped the results output here could give planners and policymakers greater insight into spatiotemporal dynamics on transfer accessibility, and help to establish an effective and efficient integrated transit system.     

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。     

Integrating the Huff Model and Floating Catchment Area Methods to Analyze Spatial Access to Healthcare Services

Analysis of spatial access to healthcare services is critical for effective health resource planning. Gravity‐based spatial access models have been widely used to estimate spatial access to healthcare services. Among them, the floating catchment area (FCA) methods have been proved to be informative and helpful to the designation of Health Professional Shortage Areas (HPSAs). This article integrates the Huff Model with the FCA method to articulate population selection on services. Through the proposed approach, population demand on healthcare services is adjusted by a Huff Model‐based selection probability that reflects the impacts of both distance impedance and service site capacity. The new approach moderates the over‐ or under‐estimating of population demand that occurred with previous methods. Furthermore, the method uses a continuous distance impedance weight function instead of the arbitrarily defined subzones of previous studies. A case study of spatial access to primary care in Springfield, MO, showed that the proposed method can effectively moderate the population demand on service sites and therefore can generate more reliable spatial access measures.     

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.     

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.     

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.     

基于GIS的两步移动搜寻法在北京市就医空间可达性评价中的应用

传统上用行政区内每千人病床数等指标来评价就医的空间可达性,并未考虑医院(供给)与人口(需求)的空间分布差异性及两者可跨越行政区界的潜在相互作用。基于GIS的移动搜寻法使用较小普查单元的人口数据,解决了内在的人口空间分布问题;移动搜寻域可以跨越行政区界,更合理地考虑病人与医院潜在的相互作用。本文通过北京市就医空间可达性的实证研究,展现了基于GIS的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。     

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。     

面向未来的智慧农业气象精细化服务系统的设计

针对我国当前农业气象服务模式中存在的产品粗放,服务手段单一,基层农气服务人员及农气专家参与程度低,缺乏为农户尤其是农业大户提供精细化、个性化、专业化的产品服务能力,因而不能很好地满足山地丘陵地区农业气象服务的需求等问题,本文设计了一种新型的农业气象精细化智能服务模式.该模式既考虑到方便、快捷地收集用户的个性化服务需求信息,又考虑到不增加业务工作人员的投入,设计了方便的系统和工具,吸引农业气象业务工作人员、基层农业气象服务人员、农技专家等多方协作参与,实现了信息互联共享,高效智能地为农业生产企业或个人提供精细化、智慧化、专业化的农业气象服务,并在重庆成功地进行了试点应用.结果表明,该模式能够较好地解决重庆地区的精细化、智慧化和专业化的农业气象服务方面的需求.     

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。     

空间信息服务质量评价

随着信息技术在测绘领域的广泛应用和信息化测绘的广泛实践,测绘不再只是提供地图或地图数据,而是提供包括空间数据在内的空间信息服务.首先提出空间信息服务质量是由空间数据质量、信息可达度以及信息交互质量三个质量指标决定的,其中每一个质量指标又包括若干下级质量指标,以此构成一个地理信息服务质量的指标树.在构建空间信息服务质量指...     

基于GIS的公共图书馆空间可达性分析

图书馆是公共文化服务的重要资源,其空间分布对城市科技文化服务能力具有重要影响。对公共图书馆的资源配置、空间分布现状进行研究,以期能为相关部门提供决策支持。以北京市主城区为例,采用高斯两步移动搜寻法,从供需角度定量分析了研究区内基于自驾和公共交通出行方式下的公共图书馆空间可达性。出行时间通过调用准确度更高的百度地图API得到。结果表明,北京市主城区公共图书馆的空间可达性整体较好,但资源布局不均衡,自驾出行方式可达性整体上优于公共交通出行方式,后期需增加移动图书馆并改善公共交通,以期提高整体服务能力。     

农村中小学布局调整之空间可达性分析——以河南省巩义市初级中学为例

中小学布局调整是教育主管部门面临的一项重要任务,涉及教育资源的公平分配和合理利用,影响到义务教育法的落实和实施.在探讨中小学布局调整原理与方法的基础上,使用地理信息系统(GIS)技术建立人口分布、学校分布和交通条件等数据库,计算空间可达性指标,定量分析每一个居住区位学生上学的便捷程度,评估教育资源的空间分布差异,为学校布局规划提供重要的参考依据.使用比例模型、最近距离模型、机会积累模型、重力模型和改进重力模型,以巩义市初级中学为例,揭示学校分布与人口分布之间的关系,期望为农村中小学布局调整提供评估方法和规划依据.案例研究发现:农村义务教育在资源配置、最近入学距离、择校机会、供需平衡方面仍有一定的不均衡性.建议使用GIS和空间可达性指标评估中小学布局调整的公平性;进一步探索学生择校的空间规律,并使用Huff模型模拟学校与学生的最佳配置,为布局调整奠定定量分析基础.     

城市公共服务设施优化配置模型研究的近期进展与展望

城市公共服务设施优化配置是实现城市公共服务均等化的必要途径。近年来，时空大数据、智能决策与仿真等技术蓬勃发展，引发了城市公共服务设施配置模型研究的革命。基于以上时代背景，本文对城市公共服务设施优化配置模型的近期研究进展进行了总结和展望：①优化决策模型朝着精细化方向快速发展，优化决策目标将更加多元化；②多源地理大数据和时空数据挖掘方法的城市公共服务需求建模动态化；③多目标群智能优化算法使城市公共服务设施优化决策朝着智能化的方向发展。随着大数据、云计算、并行计算和人工智能等新技术在GIS领域的广泛应用与集成，城市公共服务设施优化配置模型将越来越朝着精细化和智能化的方向发展。     

The accessibility analysis of multiple public facilities in the central urban areas based on multi-transportation modes: A study in Chengdu

With the rapid development of social economy in Chengdu, it is of great significance to analyze the accessibility of a public facilities resources, and services in respective regions for the spatial planning of public facilities and the optimization of urban construction in Chengdu. Most existing studies only consider the accessibility of a single public facility under a single transportation mode studying facilities at the same level. In this research, with the consideration of all these factors mentioned above, an improved 3-step floating catchment area (3SFCA) model of multi-transportation modes is introduced to analyze the accessibility and spatial distribution of multiple types of public facilities under multiple traffic modes. The new model classifies the grade of public facilities and calculates the service accessibility of public facilities under the driving, public transport, cycling, and walking modes in the five dimensions of education, medical care, commerce, transportation, and leisure in the central urban areas of Chengdu. Through the comparative analysis of multiple models, we found that the improved 3SFCA can more accurately evaluate the accessibility of all dimensions of public facilities in central urban areas of Chengdu. The accessibility of compound public facilities in the central city is excellent. With the gradual expansion to the outward areas, the diversity and accessibility of compound public facilities gradually decreases. Furthermore, the accessibility distribution of public facilities in the study area is not balanced. The accessibility between the central urban areas and the marginal areas differs greatly and the spatial differentiation is substantial.     

Accessibility tradeoffs in public transit planning

 Spatial accessibility is a critical consideration in the provision of services, both public and private. In public transit planning, accessibility is comprised of access and geographic coverage. Interestingly, these two considerations are somewhat at odds with each other. Access is important because it is the process associated with getting to and departing from the service. Such access is typically perceived of in spatial terms as the physical proximity to transit stops or stations. Additional stops along a route usually mean greater access, because a stop is more likely to be within an acceptable walking/driving standard for a larger number of people. On the other hand, more stops and greater access slow transit travel speeds, thereby decreasing the area of service reachable given a travel time budget. More stops along a route translate to greater service interruption and longer travel times. The faster the travel time, the more desirable the service. Further, if travel times become excessive, then user demand for service will decrease. All of this means that stop spacing along a route is central to accessibility, as it is a tradeoff of access (more stops) and geographic coverage (service efficiency through less stops). This paper details modeling approaches for addressing accessibility concerns in an integrated fashion. Bus-based transit service in Columbus, Ohio will be utilized to illustrate the usefulness of these approaches in transit planning. Received: September 2002 / Accepted: January 2003 This research was supported in part by an Ohio State University seed grant.     

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。     

乡村地理信息服务模式探讨与实现技术

地理信息服务聚合是将服务按照业务流程需求集成为更加复杂的服务,从而提高空间信息服务的复用能力,节约地理信息服务集成的成本。本文基于地理信息服务及乡村数据的特点,提出了一种基于补偿服务机制的地理信息服务无缝聚合的方法,聚合不同来源的服务,实现了分布式数据的无缝聚合显示及共享。     

成都市基本公共服务空间格局演化分析

基本公共服务是21世纪公共行政和政府改革的核心理念。本文以2015年地理国情普查数据成果和2016年地理国情监测数据成果作基础,从基本公共教育、基本医疗卫生、基本社会服务、公共文化体育、公园绿地等5个方面构建指标体系,综合分析成都市2015—2016年基本公共服务空间格局演化情况。分析结果表明:成都市基本公共服务空间格局呈现出以中心城区为中心向四周呈辐射状逐渐变差的特征;2015—2016年成都市基本公共服务变化范围较大,局部变化明显,变化区域分散,基本公共服务水平增加区域占全市面积的47.45%,基本医疗卫生机构和公园绿地设施的增加是导致基本公共服务水平提升的主要原因。     

基于SOAP的海量空间数据服务

随着网络GIS应用需求的迅速增长,为海量空间数据建立高速的共享机制已经成为研究热点。提供了基于SOAP的海量空间数据服务方案,将空间数据服务分为两种应用类型,即使用GML用于数据量小的空间数据服务和FTP处理数据量大的空间数据服务。通过在AM/FM系统中应用实践及分析,使用这种方案不仅可以解决数据共享与集成,而且能够为目前的GIS应用提供功能完整、稳定可靠的数据服务。