北京城市公共服务设施空间分布均衡性研究

利用空间分析和数理统计工具研究2014年北京市教育、医疗等城市公共服务设施空间分布的均衡性。以市域各街道和乡镇为评价单元,构建供给指数、需求指数度量各单元内城市公共服务设施的供给和需求,据此分析和评判北京市城市公共服务设施的空间分布及服务质量的均衡性。研究结果表明:在市域尺度上,由于城市发展历史的影响,北京城市公共服务设施空间分布均衡性呈现核心-边缘的格局;在区县尺度上,受行政体系和城镇体系的等级性影响,均衡性程度高低与城镇等级高低相一致;公共服务设施的供给指数与需求指数相关性显著,可判定设施空间分布总体上比较均衡;通过空间叠加分析发现北京市存在设施供给和需求不匹配的区域,其中教育设施、城市公园设施和医疗设施空间布局的均衡程度高于文体设施。     

新重力P中值模型及其在城市综合医院区位决策中的实证检验——以无锡市为例

区位—分配模型是实现公共服务设施最适配置的有效方法之一。传统的P中值模型以效率作为导向,采用“邻近分配”规则,不考虑设施容量(规模),难以适应城市综合医院供需之间相互作用规律下适度均衡、居民随机概率式选择和区位与规模同步求解的布局要求。本文尝试以P中值模型为基础框架,在对P中值模型来源及其适用性进行分析的基础上,构建出基于供需双方(居民—综合医院)空间相互作用的重力P中值模型。新模型通过纳入“邻近就医”最大出行成本因子,确保居民至少邻近1所综合医院(保障空间公平);通过追求总加权出行成本最小化,确保设施空间配置效率;通过纳入设施容量规模因子实现设施区位和规模同时求解;通过纳入最小规模因子,保障设施规模效率和服务质量公平。进一步通过无锡市区综合医院空间配置进行实证检验发现：采用新模型优化后,综合医院空间配置更加公平、居民邻近就医更加便捷,且能够实现与社区卫生设施协同布局,使整个医疗设施体系空间布局更加合理。本文构建的新重力P中值模型(模型的变量参数可作适当调整)可用于竞争型公共设施区位决策,为相关设施布局调整或者规划提供决策依据。     

Estimating spatial efficiency using cyber search,GIS, and spatial optimization: a case study of fire service deployment in Los Angeles County

ABSTRACT

The efficiency of public investments and services has been of interest to geographic researchers for several decades. While in the private sector inefficiency often leads to higher prices, loss of competitiveness, and loss of business, in the public sector inefficiency in service provision does not necessarily lead to immediate changes. In many cases, it is not an entirely easy task to analyze a particular service as appropriate data may be difficult to obtain and hidden in detailed budgets. In this paper, we develop an integrative approach that uses cyber search, Geographic Information System (GIS), and spatial optimization to estimate the spatial efficiency of fire protection services in Los Angeles (LA) County. We develop a cyber-search process to identify current deployment patterns of fire stations across the major urban region of LA County. We compare the results of our search to existing databases. Using spatial optimization, we estimate the level of deployment that is needed to meet desired coverage levels based upon the location of an ideal fire station pattern, and then compare this ideal level of deployment to the existing system as a means of estimating spatial efficiency. GIS is adopted throughout the paper to simulate the demand locations, to conduct location-based spatial analysis, to visualize fire station data, and to map model simulation results. Finally, we show that the existing system in LA County has considerable room for improvement. The methodology presented in this paper is both novel and groundbreaking, and the automated assessments are readily transferable to other counties and jurisdictions.     

竞争型公共设施区位决策——概念、选址原则及模型构建

竞争型公共设施竞争性、公益性并存,其区位决策相对更加复杂。首先提出了“竞争型公共设施”的概念,指出“兼顾效率与公平的空间均衡”是其选址的基本原则,并概括出具体选址要求：遵循供需双方的空间相互作用模式、限制至邻近设施的最大出行成本、追求总出行成本最小化、约束设施规模门槛、与低层级设施在出行成本上相区分等。其次构建了基于概率分配规则的重力P中值模型,通过纳入设施规模因子实现区位和规模同步求解,并对邻近设施最大出行成本和设施最小规模进行约束,以实现空间公平-效率、服务质量公平与规模效率等多重目标。最后经过实证检验,优化后的设施布局更为均衡合理。     

基于潜能模型的医疗设施空间可达性评价方法

空间可达性是评价医疗设施布局合理与否的重要指标,传统的医疗设施空间可达性评价,或者从医疗服务供需状况着手,或者从供需双方之间距离因素着手,均无法全面评价居民实际所能获取的医疗资源。本文采用基于潜能模型的评价方法对江苏省如东县医疗设施空间可达性进行分析研究,该方法综合考虑了医疗设施服务能力、居民点人口数量、医疗设施与居民点之间的出行阻抗。研究表明,通过选取合适的出行摩擦系数,该方法能够较为全面准确地测度较小研究单元的医疗设施空间可达性,辅以GIS技术,可以很直观地揭示研究区域内医疗设施空间可达性差异,结合公共卫生管理部门制定的医疗资源配置标准,还可较为准确判定缺医地区,为政府相关部门规划决策提供依据。     

广州长者饭堂供需匹配的类型、差异及调整思路

以广州市长者饭堂为研究对象,采用百度地图API、居民点POI、广州市为老综合服务平台等多源数据,综合考虑可达性和运营可行性,并对两步移动搜索法进行改进,通过转换测度结果和过程变量,刻画长者饭堂的供需匹配情景。研究发现：1）广州长者饭堂在“行政单元全覆盖”推广下供需空间匹配度六成合格,形成平衡型、剩余型和短缺型的数量“631”结构;2）供给和需求的主体优势、空间分布错位,需求获取优势高于供给,空间呈现“内低外高—单中心圈层”供给结构与“南强北弱—多核网状”需求结构;3）出行优势中心两级分化,成为剩余型和短缺型的主要聚集地。主核心片内出现“老城中心洼地”和“黄埔高地”,外围行政区出现多个剩余小高地或短缺谷地。最后,为精准干预长者饭堂网点布局,提出存量提升、配对整合、存量精简等适宜不同空间关联条件的不匹配型优化思路,优先考虑强空间关联的剩余型和短缺型街道配对整合;以及直接提升、主动提升、被动提升的匹配型提升思路,实现广州长者饭堂全覆盖全匹配目标。     

GIS and geometric representation in facility location problems

Abstract

A neglected aspect of facility location problems is the geometric representation of the facilities sited and clients served. Point objects represent these entities in most facility location problems. This can cause solution error and limit the range of potential solutions. The increasing capabilities of geographical information systems (GIS) to represent, store and manipulate spatial entities provides a substantial but unrealized potential for more sophisticated geometric representation in facility location problems. This paper provides a framework for realizing this potential. Specifically, this paper: (i) synthesizes existing formulations; (ii) develops a unified mathematical framework; (iii) identifies feasible computational strategies that can be implemented within a GIS framework, and; (iv) discusses potential GIS-based solution algorithms.     

A Sustainability Initiative to Quantify Carbon Sequestration by Campus Trees

Abstract

Over 3,900 trees on a university campus were inventoried by an instructor-led team of geography undergraduates in order to quantify the carbon sequestration associated with biomass growth. The setting of the project is described, together with its logistics, methodology, outcomes, and benefits. This hands-on project provided a team of students with several learning opportunities including an introduction to carbon sequestration, basic arboriculture, field-based measurements, mapping, geographic information systems, and biogeography concepts. A GIS geodatabase was produced containing information on tree location, species, size, biomass, carbon content, and annual CO₂ sequestration, which was later customized for integration into campus facilities management.     

Integration of genetic algorithms and GIS for optimal location search

Optimal location search is frequently required in many urban applications for siting one or more facilities. However, the search may become very complex when it involves multiple sites, various constraints and multiple‐objectives. The exhaustive blind (brute‐force) search with high‐dimensional spatial data is infeasible in solving optimization problems because of a huge combinatorial solution space. Intelligent search algorithms can help to improve the performance of spatial search. This study will demonstrate that genetic algorithms can be used with Geographical Information systems (GIS) to effectively solve the spatial decision problems for optimally sitting n sites of a facility. Detailed population and transportation data from GIS are used to facilitate the calculation of fitness functions. Multiple planning objectives are also incorporated in the GA program. Experiments indicate that the proposed method has much better performance than simulated annealing and GIS neighborhood search methods. The GA method is very convenient in finding the solution with the highest utility value.     

Combining spatial transition probabilities for stochastic simulation of categorical fields

Categorical spatial data, such as land use classes and socioeconomic statistics data, are important data sources in geographical information science (GIS). The investigation of spatial patterns implied in these data can benefit many aspects of GIS research, such as classification of spatial data, spatial data mining, and spatial uncertainty modeling. However, the discrete nature of categorical data limits the application of traditional kriging methods widely used in Gaussian random fields. In this article, we present a new probabilistic method for modeling the posterior probability of class occurrence at any target location in space-given known class labels at source data locations within a neighborhood around that prediction location. In the proposed method, transition probabilities rather than indicator covariances or variograms are used as measures of spatial structure and the conditional or posterior (multi-point) probability is approximated by a weighted combination of preposterior (two-point) transition probabilities, while accounting for spatial interdependencies often ignored by existing approaches. In addition, the connections of the proposed method with probabilistic graphical models (Bayesian networks) and weights of evidence method are also discussed. The advantages of this new proposed approach are analyzed and highlighted through a case study involving the generation of spatial patterns via sequential indicator simulation.     

Research Article. Modelling inside GIS: Part 1. Model structures,exploratory spatial data analysis and aggregation

Abstract

This is the first of two papers elaborating a framework for embedding urban models within GIS. This framework is based upon using the display capabilities of GIS as the user interface to the conventional modelling process, beginning with data selection and analysis, moving to model specification and calibration, and thence to prediction. In this paper, we outline how various stages in this process based on purpose-built software outside the system, are accessed and operated through the GIS. We first deal with display based on thematic maps, surfaces, graphs and linked windows, standard to any data from whatever source, be it observations, model estimates or predictions. We then describe how various datasets are selected, how the spatial system can be partitioned or aggregated, and how rudimentary exploratory spatial data analysis enables scatterplots to be associated with thematic maps. We illustrate all these functions and operations using the proprietary GIS ARC-INFO applied to population data at the tract level in the Buffalo region. In the second part of the paper, various residential location models are outlined and the full modelling framework is assembled and demonstrated.     

Regularities in Spatial Information Processing: Implications for Modeling Destination Choice

This paper investigates the determinants of spatial knowledge and how our knowledge of space varies according to geographic location. By using data on U.S. city names recalled at 22 test locations, a multivariate model of the information surface specific to each test location is calibrated. This model links the probability of a city being recalled from memory to its distance from the test site, its population size, its location with respect to other cities, and whether or not it is a state capital. The paper then suggests that these recall data provide information on spatial knowledge surfaces from which large-scale spatial choices, such as migration destinations, are made. Results from the analysis lend further evidence to the idea that spatial knowledge is stored and processed hierarchically and that individuals underrepresent information in large clusters. Consequently, the results have important implications for modeling any spatial behavior based on individuals' spatial information surfaces. In particular, the results cast further doubt on the validity of traditional large-scale spatial choice frameworks and lend support to the competing destinations hypothesis.     

Aspects of the implementation of the GEOVIEW design

Abstract

GEOVIEW, an integrated system, uses relational database technology and a graphics package (Graphical Kernel System) to offer a flexible environment in which to develop applications of geographical information systems (GIS). It has facilities to represent data in different spatial data structures. Data are stored and retrieved efficiently by using variable length raw data. The unified representation offers the benefit of storing entities in a single relation and eases the process of overlaying different entities. GEOVIEW also provides a mechanism for tailoring user interfaces to suit the needs of different applications by means of a facility to generate macros and menus.

Processing requirements for GIS applications can be supported by using tools provided by relational database technology and by graphics packages. High-level language interfaces which can process dynamic statements and bind dynamic variables are needed to develop an efficient database interface module. A graphics segment facility is essential to provide editing functions and to maximize the use of the local processing power of graphics workstations in the graphics interface module. Further improvements in performance can be made by using the array fetch facility and linear keys for spatial searching.     

Guest Editorial Latest developments in GIS/LIS

Abstract

Significant achievements have taken place in Geographical/Land Information Systems (GIS/LIS). An attempt is made to give an overview of the state of the art as well as a vision of progress still to be accomplished. Key issues are discussed in various GIS/LIS activities. A generic analysis shows that most of the applications are environment-oriented. The various GIS/LIS topical issues are discussed in the order of an ascending graph, including data capture, data structure and modelling, data quality and standards, institutions, ethics, education, visualization and interface, spatial decision support systems, and applications. Finally a brief assessment of the role and nature of GIS is made. It is noted, in particular, that there are great discrepancies in the spread and success of GIS/LIS at the international level. This is true between developed and developing countries, but the case can also be made between western industrialized countries. It is also observed that there is an increasing number of professions involved in GIS/LIS activities and an increasing collaboration between those professions. Finally, it is observed that GIS/LIS are used predominantly as a tool to manage and keep records, although there are signs that GIS/LIS are also leading the way towards a new spatial science. This is only a 1993 ‘snap shot’, and is expected that many of the statements have only a limited life, considering the rapid changes in both theory and technology.     

绿色空间对休闲性体力活动影响的社区分异 ——以广州市为例

以广州市20个典型社区为例,构建多元线性回归模型,探讨了绿色空间对居民休闲性体力活动的影响,并剖析绿色空间对不同类型社区居民休闲性体力活动影响的作用机制。结果发现：1）不同类型社区居民的休闲性体力活动水平存在明显差异,低档社区的为782.99 MET-min/w,中档社区的为871.70 MET-min/w,高档社区的为1 227.91 MET-min/w;2）影响不同类型社区居民休闲性体力活动水平的绿色空间因素有所不同,低档社区、中档社区和高档社区的显著因子分别为“到最近公园广场距离”“邻里绿化覆盖率”和“健身活动设施数量”;3）绿色空间对休闲性体力活动水平影响的作用机制存在社区差异,低档社区居民休闲性体力活动主要受到成本作用的约束,中档社区居民主要受绿化环境作用影响,而高档社区居民主要受机会作用影响。     

Size and spatial distribution of loess slides on the Chinese Loess Plateau

ABSTRACT

The size and spatial distribution of loess slides are important for estimating the yield of eroded materials and determining the landslide risk. While previous studies have investigated landslide size distributions, the spatial distribution pattern of landslides at different spatial scales is poorly understood. The results indicate that the loess slide distribution exhibits a power-law scaling across a range of the size distribution. The mean landslide size and size distribution in the different geomorphic types are different. The double Pareto and inverse gamma functions can coincide well with the empirical probability distribution of the loess slide areas and can quantitatively reveal the rollover location, maximum probability, and scaling exponents. The frequency of loess slides increases with mean monthly precipitation. Moreover, point distance analysis showed that > 80% of landslides are located < 3 km from other loess slides. We found that the loess slides at the two study sites (Zhidan and Luochuan County) in northern Shaanxi Province, China show a significant clustered distribution. Furthermore, analysis results of the correlated fractal dimension show that the landslides exhibit a dispersed distribution at smaller spatial scales and a clustered distribution at larger spatial scales.     

开放式GIS在大数据时代的机遇与障碍

GIS 领域的发展在21 纪初走到了十字路口。本文旨在讨论下一个阶段GIS 发展的多个愿景,而新兴的开放式GIS应作为一个指导思想。开放式GIS包含8 个维度：数据、软件、硬件、规范、研究、出版、资金和教育。对于GIS 研究团体,开放式GIS 提供了4 个令人振奋的机会：①技术发展。技术的发展与突破可用于解决空间上的海量数据所带来的问题;②应用开发。主要是用于集体或个人决策的应用程序的开发;③增加全民参与的机会。地理科学可以发展成一种开放性的全民科学,人们将对日益变化的地球增进了解;④教育的机遇。通过开放式GIS能更好地实现全民地理科学教育。虽然开放式GIS 的实现存在着学术、法律、社会、政治和环境等障碍,但可以肯定的是,开放式GIS在未来的科学研究和教育方面将会变得越来越重要。     

Resource use in manual digitization A case study of the Patuxent basin geographical information system database

Abstract

In the face of limited and declining budgets, the estimation of costs involved in implementing a geographical information system (GIS) deserves attention. One of the major procedures inherent in the use of GIS is the task of digitizing existing maps. This step is not only the first but may also occur at various stages of the implementation. There is, however, a lack of information on the cost of digitizing. This paper identifies the costs of an intensive effort at manual digitizing over a period of eleven months using the ARC/INFO GIS on a Prime 9650 mini-computer. General costs for digitizing one layer of information from a U.S. Geological Survey 1:24 000 quadrangle are derived. Although the results are based on factors which are unique to this study, the author believes that the findings provide useful bases for estimating costs of digitizing.     

基于生活圈理论的合肥市城市养老服务设施空间配置合理性研究

基于生活圈理论,构建了城市养老服务设施空间配置合理性评价标准,运用GIS空间分析方法,从城市、行政区及街道等不同空间层面对合肥市城市养老服务设施空间分布特征及配置合理性进行分析。研究发现：1）合肥市城市养老供给以社区养老服务为主要类型,城市养老服务设施建设数量和体量在4个行政区间存有较大差异;2）合肥市城市养老服务设施空间分布、配置合理性均由城市中心向外围地区呈圈层式递减,城市新区是养老服务供给的薄弱地段;3）合肥市城市养老服务设施空间配置合理性在街道层面差异更显著,覆盖率相似街道呈现明显的空间聚集特征。     

Database design for a multi-scale spatial information system

Abstract

Growth in the available quantities of digital geographical data has led to major problems in maintaining and integrating data from multiple sources, required by users at differing levels of generalization. Existing GIS and associated database management systems provide few facilities specifically intended for handling spatial data at multiple scales and require time consuming manual intervention to control update and retain consistency between representations. In this paper the GEODYSSEY conceptual design for a multi-scale, multiple representation spatial database is presented and the results of experimental implementation of several aspects of the design are described. Object-oriented, deductive and procedural programming techniques have been applied in several contexts: automated update software, using probabilistic reasoning; deductive query processing using explicit stored semantic and spatial relations combined with geometric data; multiresolution spatial data access methods combining poini, line, area and surface geometry; and triangulation-based generalization software that detects and resolves topological inconsistency.