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。     

制造业与生产性服务业聚集及空间可分性研究——以深圳市为例

制造业和生产性服务业各自具有聚集特性,同时生产性服务业可不受制于空间约束,通过信息通信和交通运输使得与制造业在空间上具有可分性。现有产业空间可分性研究主要以定性分析为主,缺乏有效的测度指标。本文利用全局和局域Moran指数及其双变量变体,结合Moran散点图和LISA图,对深圳市的制造业和生产性服务业企业空间关联格局进行定量分析。研究表明,深圳市生产性服务业与制造业空间自相关性明显,且两者具有空间可分性,这为合理进行制造业和生产性服务业的空间规划布局提供了新思路。     

基于步行安全的生活圈可达性分析——以武汉市为例

在城市交通出行中,行人作为弱势群体,步行安全显得尤为重要.本研究通过街景图片识别三类步行设施,并叠加机动车流量与人口分布综合计算步行安全性.以步行安全性为道路网阻抗,计算分析了武汉市步行指数及医疗、绿地资源的可达性.结果表明:武汉市步行设施建设有待提升;步行安全存在明显的地区分异,在"两江三镇"分割的情况下,汉口地区步...     

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。     

Measuring Accessibility with GIS-Tools: A Case Study of the Wild Coast of South Africa

Although most GIS-based planning support have the capacity to show the location and attributes of different places, very few GIS-based systems are able to describe adequately the degree of spatial interaction, or the geographic accessibility, between places. The Faculty of Geographical Sciences of the Utrecht University (The Netherlands) and the South African Council for Scientific and Industrial Research (CSIR), are developing a methodology to address the problem of measuring accessibility by integrating specialised GIS software (FlowMap) that measures the geographic accessibility between locations within a spatial decision support system (AccessMap). The resulting GIS-tool is applied to the Wild Coast area in South Africa. In this region a lack of accessibility to market centres is perceived as one of the major constraints of economic development in the region.     

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...     

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.     

基于GIS的医疗资源可达性分析——以吉林省白城市为例

空间可达性是评价医疗资源分布合理性的重要指标之一,借助GIS强大的空间分析功能,可以对医疗资源可达性进行科学的分析与评价。本文尝试基于白城市的行政区划、交通数据以及医疗资源相关资料,使用GIS技术、空间可达性指标和改进的潜能模型对医疗资源可达性进行综合分析,为医疗资源的规划及分配提供决策参考。     

基于MODIS植被丰度的沙漠化界线提取方法探究——以陕甘宁地区为例

以陕甘宁地区为研究区、2001—2015年的MODIS遥感影像为数据源,基于MODIS像元的植被丰度提出了累积曲线梯度变化法,通过提取沙漠化界线确定了用植被丰度表达的界线指标,讨论了陕甘宁地区的沙漠化变化。结果表明:(1)基于数学统计分析方法的累积曲线梯度变化法,方法简单、可操作性强,为沙漠化的定量分析与动态监测提供了新方法;(2)以植被丰度15%为指标作为陕甘宁地区的沙漠化界线,发现在这15年间,陕甘宁地区的沙漠化呈现在波动中不断改善的总体趋势。     

Mapping Wetland Areas Using Landsat-Derived NDVI and LSWI: A Case Study of West Songnen Plain,Northeast China

Increasing interest in wetlands for environmental management requires an understanding of the location, spatial extent, and configuration of the resource. The National Wetlands Inventory is the most commonly used data source for this information. However, its accuracy is limited in some contexts, such as agricultural and forested wetlands. An large number of studies have mapped wetlands worldwide from the perspective of land use and land cover change. However, information on the actual wetland planting areas annually is limited, which greatly impacts ongoing research. In this case study of the West Songnen Plain, we developed a simple algorithm for the quick mapping of wetlands by utilizing their unique physical features, such as annual display of phenological land-cover change of exposed soils, shallow flooding water, and plants from multi-temporal Landsat images. Temporal variations of the Normalized Difference Vegetation Index (NDVI) and Land Surface Water Index (LSWI) derived from Landsat images in 2010 for wetlands at different growth stages were analyzed. Results show that during the ante-tillering phase, the NDVI value (above zero) is lower than the LSWI value of paddies because of flooding of shallow water; during the reproductive and ripening phases, the NDVI value is higher than the LSWI value (above zero); and during the post-harvest wetland planting phase, the NDVI value is still higher than the LSWI value, but the LSWI value is negative. Wetland areas can be detected using one or two images in the optimum time window. The algorithm based on the difference of NDVI and LSWI values derived from Landsat images was used to extract the actual wetland planting area. Validated alongside statistical data, the algorithm showed high accuracy. Therefore, this algorithm highlights the unique features of wetlands and can help in mapping the actual wetland area annually on a regional scale. Results further indicate that the new method has a classification accuracy of 92 %. In comparison, two traditional methods based on Landsat-7/ETM registered accuracy rates of only 83 % and 87 % respectively.     

基于GIS的复杂环境空间通达性预测方法研究

在野外无拓扑道路的空间环境中进行快速行军和野外抢险工作时,快速准确地实现空间目的点最佳路径的构建,是提高行军和抢险效率的关键。针对复杂空间环境中路径搜索问题,提出了一种基于GIS的复杂环境空间可达性预测方法。引入高程、坡度、植被等地形因子,通过对地形因子权重关系的分析,实现算法的改进。利用GIS技术结合改进A*算法,实现对空间地域通达性的预测,为空间复杂环境中的最佳路径搜索和选择提供决策支持。以桂林市某山区地形DEM数据为例,采用改进A*算法实现空间最佳路径的分析和计算。仿真和实测结果表明,该方法具有一定的实用性。     

Model Building to Investigate the Role of Spatial Location in Classifying Satellite Image Using SVM,CART and mBACT: A Case Study

This paper investigates the importance of spatial location of pixels in terms of row-column as an additional explanatory variable in classification along with available spectral bands of remotely sensed data. In view of this, a forward step-wise variable selection algorithm is used to select significant bands/variables and build an optimal model to extract the maximum accuracy. Author performed a case study on the area of town of Wolfville acquired by LANDSAT 5 TM data containing six 30 m resolution spectral bands and pixel location as an additional variable. Data are classified into seven classes using three advanced classifiers i.e. classification and regression trees (CART), support vector machines (SVM) and multi-class Bayesian additive classification tree (mBACT). Traditionally, it is assumed that addition of more explanatory variables always increase the accuracy of classified satellite images. However, results of this study show that adding more variables may sometimes confuse the classifier, that is, if selected carefully, fewer variables can provide the more accurate classification. Importance of row-column information turns out to be more beneficial for mBACT followed by SVM. Interestingly, spatial locations did not turn out to be useful for CART. Based on the findings of this study, mBACT appears to be a slightly better classifier than SVM and a substantially better than CART.     

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。     

利用网络游记分析不同类型游客的旅游流网络特征差异——以云南省为例

旅游流网络分析对理解游客的目的地选择以及目的地在旅游流网络中承担的角色有重要意义。以中国云南省为例,基于网络游记数据挖掘游客的多维度偏好,并以此对游客聚类,进而划分出不同类型的游客群体。针对各类游客游记中的旅游目的地序列建立旅游流网络,并从多个角度分析各类游客旅游流网络的结构特征和各目的地节点的角色特征。结果表明,不同类别游客的旅游流网络在整体结构上各有特点,反映出旅游目的地不同的空间交互模式和网络中心化程度。此外,部分旅游目的地在不同类别旅游流网络中承担截然相反的角色。上述分析有助于优化旅游流网络中各节点的协作机制,辅助旅游目的地制定差异化的旅游产品。     

Assessment of Late Blight Induced Diseased Potato Crops: A Case Study for West Bengal District Using Temporal AWiFS and MODIS Data

Remote sensing technology becomes an effective and inexpensive technique for detecting disease in vegetation. In this study, an attempt has been done to discriminate healthy and late blight affected crop using remote sensing based indices such as NDVI and LSWI. NDVI and LSWI spectral profiles between healthy and late blight affected crop shows large difference. Mean difference in reflectance between two acquired dates Jan. 10 and 29, 2009 crop clusters varied from 31.28 % in red band, 7.7 % in NIR band and 6.23 % in SWIR bands in healthy crops while in late blight affected crops it is ?15.5 % in red, 44.4 % in NIR and ?14.61 % in SWIR bands. Negative percentage differences in reflectance indicate reflectance increases from Jan. 10, 2009 to Jan. 29, 2009, while positive difference indicate decrease in reflectance between the two dates. Since potato is an irrigated crop, these differences in reflectance are attributed to prevalent disease at that time. It is found that severely affected areas are Bardhman, Arambag, Bishnupur, Ghatal and Hugli taluka with crop damage areas are 4036.66, 1138.68, 2025.23, 469.15, and 380.08 ha, respectively.     

Using GIS in Areawide Pest Management: A Case Study in South Dakota

Infestations of corn rootworms (Coleoptera: Chrysomelidae) create economic and environmental concerns in the Corn Belt region of the United States. To supplement the population control tactics of areawide pest management programs, we believe that a better understanding of the spatial relationships between biotic and abiotic or physical factors at the landscape scale is needed. Our research used several geographical information systems (GIS) and spatial analytical techniques to examine relationships between corn rootworm metapopulation dynamics, soil texture, and elevation. Within GIS, several spatially explicit procedures were used that include an interpolation technique, spatial autocorrelation analysis, and contingency analysis. Corn rootworm metapopulation distributions were found to be aggregated and related to soil texture and elevation. We review techniques and discuss our preferences for using particular spatially explicit procedures. The information derived from the spatial analyses demonstrates how GIS can be used in areawide pest management to provide inputs for spatially explicit models to predict future pest populations and formulate more well‐informed pest management decisions. The techniques described in this paper could easily be extended to study the spatial dynamics between other pest populations in agricultural landscapes.     

WebGIS在美国南加州数字城市建设中的应用实例分析

从介绍WebGIS技术在南加州一个成功应用项目--加州橙县土地公共文档查询显示和电子商务系统的技术路线和体系结构入手,分析了当前几个主要WebGIS软件的基本特点和存在的技术问题.在此基础上,引入了可以改善目前WebGIS技术领域内弊端的一种新方法--基于SVG矢量图形格式的WebGIS技术,同时给出了这一技术的基本思路和优点,并通过系统的开发实践证明其响应速度、功能与图形效果.这一WebGIS应用展示了基于SVG格式的WebGIS技术的强大活力.通过与其他系统的无缝集成,如与电子商务系统,文档管理系统,以及办公自动化系统等,WebGIS将GIS技术的应用推上一个新台阶,使得GIS技术在数字化城市的建设中发挥更大的作用.     

基于空间抽样的上海市GlobeLand302020数据精度评估

针对上海GlobeLand302020土地覆盖产品,应用顾及空间异质性的类别-异质性分层抽样方法进行抽样,将研究区各地图类别划分为匀质区和异质区子类,按照内曼分配方法布设验证样本,在研究区域内抽取2500个验证像素,并参考同时期多源Google Earth高分遥感影像数据进行样本判读,获得参考分类即真实类别信息,对区域...     

Evaluating the Performance of Multi-Class and Single-Class Classification Approaches for Mountain Agriculture Extraction Using Time-Series NDVI

Supervised multi-class classification (MCC) approach is widely being used for regional-level land use–land cover (LULC) mapping and monitoring. However, it becomes inefficient if the end user wants to map only one particular class. Therefore, an improved single-class classification (SCC) approach is required for quick and reliable map production purpose. In this regard, the current study attempts to evaluate the performance of MCC and SCC approaches for extracting mountain agriculture area using time-series normalized differential vegetation index (NDVI). At first, samples of eight LULC classes were acquired using Google Earth image, and corresponding temporal signatures (TS) were extracted from time-series NDVI to perform classification using minimum distance to mean (MDM) and spectral angle mapper (i.e., multi-class SAM—MCSAM) under MCC approach. Secondly, under SCC approach, the TS of three agriculture classes (i.e., agriculture, mixed agriculture and plantation) were utilized as a reference to extract agriculture extent using Euclidean distance (ED) and SAM (i.e., single-class SAM—SCSAM) algorithms. The area of all four maps (i.e., MDM—19.77% of total geographical area (TGA), MCSAM—21.07% of TGA, ED—15.23% of TGA, SCSAM—13.85% of TGA) was compared with reference agriculture area (14.54% of TGA) of global land cover product, and SCC-based maps were found to have close agreement. Also, the class-wise detection accuracy was evaluated using random sample point-based error matrix which reveals the better performance of ED-based map than rest three maps in terms of overall accuracy and kappa coefficient.     

Spatial Supermarket Redlining and Neighborhood Vulnerability: A Case Study of Hartford,Connecticut

The disinclination of chain supermarkets to locate or relocate existing stores from inner city impoverished neighborhoods to affluent suburbs is termed ‘spatial supermarket redlining’. This study attempts to map and understand the effects of potential spatial supermarket redlining on food access in urban disadvantaged neighborhoods of Hartford, Connecticut. Using a combination of statistical and spatial analysis, we first built a Supermarket Redlining Index (SuRI) from five indicators (sales volume, employee count, accepts food coupons from federally assisted programs, and size and population density of the service area) to rank supermarkets in the order of their importance. Second, to understand the effects of supermarket closures in the inner city, a Supermarket Redlining Impact Model (SuRIM) was built with 11 indicators describing both socioeconomic and food access vulnerabilities. The interaction of these vulnerabilities identified neighborhoods that are maximally impacted by spatial supermarket redlining. Results mapped critical areas in the inner city of Hartford where, if a nearby supermarket closed down or relocated to a suburb with limited mitigation efforts to fill the grocery gap, a large number of minority, poor, and disadvantaged residents would experience difficulties to access healthy food, leading to food insecurity or perhaps a food desert. In conclusion we suggest mitigation efforts to reduce this impact of large supermarket closures.