共查询到19条相似文献，搜索用时 125 毫秒
1.
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。 相似文献
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为降低可达性度量的实现难度,弥补现有GIS软件没有集成可达性分析模型或方法的不足,在详尽分析有关模型或方法与GIS集成研究现状的基础上,提出以改进潜能模型作度量模型,按GIS内部集成方式,使用面向ArcGIS 10的Python脚本编程技术集成开发可达性分析工具的设想,对可达性潜能模型分析原理、工具开发环境配置、使用数据的预处理要求、工具的具体设计流程和实现方法等作了详细叙述。最后以评价某市小学教育资源空间布局合理性为例,阐述工具在实际应用中应采取的使用方法和流程,实例评价结果验证工具开发的有效性。 相似文献
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为了让现有的时空可达性分析能够更好地满足实际应用需求,帮助改善城市交通状况,该文从传统的、基于GIS的以及基于效用的度量方法3个方面分类归纳了现有的时空可达性度量方法,总结了各种时空可达性度量方法的优缺点,讨论了时空可达性模型的应用现状,指出这些方法存在的问题和局限性:①度量方法中,只考虑单一出行模式,但实际出行中存在不同代步工具的换乘,应当考虑公交-地铁,汽车-公交等换乘情况;②方法的前提是假设区域内个体差异很小,忽略了地域不同个体的差异性;③不适用于交通不发达的小型城镇区域;④对最后一公里问题未提出有效的解决策略。最后,展望了时空可达性的相关热点研究方向。 相似文献
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公园绿地是城市公共基础设施的重要组成部分,公园合理的空间布局有助于城市居民便捷和公平地享用其服务功能。根据深圳市建筑普查数据和细粒度的人口数据提取住房信息,结合公园绿地数据和土地利用情况,针对不同类型公园的服务能力分别采用合适的可达性计算方法,从住房、社区和街道三个尺度评价深圳公园绿地可达性,结果表明:社区公园可达性一般,仅57.62%的社区的居民步行500 m以内能到达最近的社区公园;城市公园可达性总体较好,95.87%的社区市民步行前往最近城市公园所需时间在20 min以内。然而,大鹏半岛无城市公园,且多为自然生态保护区,市民到达城市公园所需时间长。社区公园可达性好的区域呈带状分布于深圳南部各区,城市公园高可达性区域呈多核围绕在各区行政中心。 相似文献
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针对计算空间场景相似性的TDD(Topology-Direction-Distance)模型的局限,提出一种基于改进的TDD模型来度量实体数目相同的场景相似度的算法.该算法以TDD模型的思想为核心,首先利用维度扩展的9交模型、详细方向关系矩阵模型和距离定量描述方法分别提取空间场景中的实体间拓扑、方向和距离特征,建立空间场景特征矩阵,实现对空间场景的表达;然后结合拓扑、方向关系的概念邻域方法和欧式距离,构建针对矢量面数据空间场景相似性度量模型;利用场景相似性度量模型进行空间场景相似性匹配;最后以深圳市福田区矢量面数据为例进行实验.实验结果表明该方法能有效度量空间场景的相似度. 相似文献
7.
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。 相似文献
8.
针对利用实时浮动车数据估计路段行程时间时存在的数据稀疏性问题,提出了构建三层神经网络模型,以目标路段与邻接路段间的特征关系为输入、目标路段与邻接路段行程时间比值为输出,利用浮动车历史大数据获取路段之间的交通时空关联关系,继而用于路段行程时间的推断。采用武汉市2014年3~7月的浮动车GPS历史数据进行验证,得到的路段行程时间估计值的平均绝对百分比误差小于25%,证明了所提方法的有效性。 相似文献
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熊念 《测绘与空间地理信息》2017,(10):105-107
社会经济数据是研究城市发展的重要因子,而传统的社会经济数据由于与空间坐标不统一,对城市发展的空间变化难以提供有力的支持。本文利用DMSP/OLS灯光数据,基于生态控制线,通过回归运算制定深圳市2010年人口指数模型,得到深圳市2010年1 km~2人口空间化图,有利于对深圳市人口的空间分布特征进行分析,为城市的绿色发展提供依据。 相似文献
11.
Space-time accessibility measures: A geocomputational algorithm with a focus on the feasible opportunity set and possible activity duration 总被引：12，自引：2，他引：12
Space-time accessibility measures have received much attention in recent years due to their sensitivity to differences in
individual ability to participate in activities in space and time. Despite the conceptual attractiveness and robustness of
space-time measures, only few attempts have been made to operationalize them to date. Research that seeks to improve space-time
accessibility measures is still sorely needed. This study seeks to enhance space-time accessibility measures through developing
a new operational method and GIS-based algorithm that better represents the space-time characteristics of urban opportunities
(e.g. their geographical distribution and opening hours) and human activity-travel behavior (e.g. delay times, minimum activity
participation time, and maximum travel time threshold). The proposed method not only takes into account the number and size
of opportunities, but also the possible activity duration at each activity location given its opening hours and the effect
of transport network topology (e.g. one-way streets, turn restrictions and over-pass). Incorporating these elements into space-time
measures helps overcome several shortcomings of previous approaches to evaluating space-time accessibility.
Received: 15 September 2002 / Accepted: 10 February 2003
A version of this paper was presented at the 98th Annual Meeting of the Association of American Geographers, Los Angeles,
March 19-23, 2002. We thank Joe Weber for providing the digital transport network with travel speeds and a version of the
geocomputational algorithm he used in his study (Weber 2001), upon which our developmental effort has been based. We are also
grateful to the helpful comments and suggestions of the reviewers. 相似文献
12.
Accessibility Futures 总被引：1，自引：0，他引：1
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. 相似文献
13.
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. 相似文献
14.
Smart card-automated fare collection systems now routinely record large volumes of data comprising the origins and destinations of travelers. Processing and analyzing these data open new opportunities in urban modeling and travel behavior research. This study seeks to develop an accurate framework for the study of urban mobility from smart card data by developing a heuristic primary location model to identify the home and work locations. The model uses journey counts as an indicator of usage regularity, visit-frequency to identify activity locations for regular commuters, and stay-time for the classification of work and home locations and activities. London is taken as a case study, and the model results were validated against survey data from the London Travel Demand Survey and volunteer survey. Results demonstrate that the proposed model is able to detect meaningful home and work places with high precision. This study offers a new and cost-effective approach to travel behavior and demand research. 相似文献
15.
GIS与Voronoi多边形在医疗服务设施地理可达性分析中的应用 总被引：5，自引：0，他引：5
王远飞 《测绘与空间地理信息》2006,29(3):77-80
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。 相似文献
16.
Ubiquitous taxi trajectory data has made it possible to apply it to different types of travel analysis. Of interest is the need to allow someone to monitor travel momentum and associated congestion in any location in space in real time. However, despite an abundant literature in taxi data visualization and its applicability to travel analysis, no easy method exists. To measure taxi travel momentum at a location, current methods require filtering taxi trajectories that stop at a location at a particular time range, which is computationally expensive. We propose an alternative, computationally cheaper way based on preprocessing vector fields from the trajectories. Algorithms are formalized for generating vector kernel density to estimate a travel-model-free vector field-based representation of travel momentum in an urban space. The algorithms are shared online as an open source GIS 3D extension called VectorKD. Using 17 million daily taxi GPS points within Beijing over a 4-day period, we demonstrate how to generate in real time a series of projections from a continuously updated vector field of taxi travel momentum to query a point of interest anywhere in a city, such as the CBD or the airport. This method allows a policy-maker to automatically identify temporal net influxes of travel demand to a location. The proposed methodology is shown to be over twenty times faster than a conventional selection query of trajectories. We also demonstrate, using taxi data entering the Beijing Capital International Airport and the CBD, how we can quantify in nearly real time the occurrence and magnitude of inbound or outbound queueing and congestion periods due to taxis cruising or waiting for passengers, all without having to fit any mathematical queueing model to the data. 相似文献
17.
Diego Bogado Tomasiello Mariana Giannotti Renato Arbex Clodoveu Davis 《Transactions in GIS》2019,23(2):203-223
Vehicle tracking is a spatio‐temporal source of high‐granularity travel time information that can be used for transportation planning. However, it is still a challenge to combine data from heterogeneous sources into a dynamic transport network, while allowing for network modifications over time. This article uses conceptual modeling to develop multi‐temporal transport networks in geographic information systems (GIS) for accessibility studies. The proposed multi‐temporal network enables accessibility studies with different temporal granularities and from any location inside the city, resulting in a flexible tool for transport and urban planning. The implemented network is tested in two case studies that focus on socially excluded people in a large global city, São Paulo, Brazil, including accessibility analyses from slum areas. It explores variations within a day and differences between transport modes across time. Case study results indicate how the accessibility is heterogeneous in low‐income regions. 相似文献
18.
近年来,快速发展的高速铁路、城际轨道等高速交通方式对旅游的影响日益显现。本文以珠三角地区运营和规划城际轨道为例,基于GIS网络分析技术和通达性指标,探讨了城际轨道通车前后对珠三角地区旅游空间格局的影响。结果表明:城轨开通将会产生显著的"时空压缩"效应,旅游景点总通达时间降幅达32.87%,旅游景点平均通达时间减少0.7 h;不同区域通达性水平提升具有差异性,城际轨道站点及其周边地区成为通达性水平提升最大的地区,随着与站点距离逐渐增加,通达性变化程度逐渐降低;城轨开通后各地区通达性水平差异逐渐缩小,并趋于均衡;城轨影响下的旅游景点通达性的影响具有"廊道效应"与"隧道效应"相结合的特征,空间格局由开通前的"中心-外围"态势向面状均衡分布格局转变。城际轨道带来的"时空压缩"效应,在扩大了旅游景点市场范围的同时,由于通行时间成本降低,进一步提高了旅游出行的效率。 相似文献
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针对现有出租车轨迹数据挖掘中时间序列邻近度量方法存在的问题,提出一种基于DBSCAN算法和改进的DTW距离的时间序列聚类算法提取具有相似性出行特征的时空模式,进而研究城市人群出行行为的时空差异。以南京市为例,结合电子地图对出行模式的空间分布特征进行分析,证明了本文所提出的方法的有效性。实验结果表明:在空间分布上,工作日出租车出行模式按照平均出行频次由高到低排序,从城市中心向四周扩散,呈中心环状分布,出行模式区域界限较为明显,同类出行模式分布区域对应相似的功能。提出了一种基于DBSCAN算法和改进的DTW距离的时间序列聚类算法提取具有相似性出行特征的时空模式,有效地分析城市人群出行行为的时空差异。 相似文献