Commuters’ non-linear response to time distances

Established analyses of labour market commuting are based on random choice models and gravity type models. In these models generalised transport costs are formulated as exponential or log-linear distance dependent functions. This paper presents empirical observations, which imply that time distances influence the commuting behaviour in a non-linear way, such that the time sensitivity is much lower for very short and long distances, whereas intermediate distances display a high time sensitivity. This is explained in a model that is parameterised and estimated. The results are important for understanding and predicting commuter behaviour. It also helps to delineate space, as in classical traditions, into local, intra-regional and extra-regional space.     

地理空间数据结合手机信令等多源数据刻画城市居民出行特征

本文提出了以地理空间数据为支撑,结合手机信令、POI等多源数据刻画城市居民出行特征的方法。首先将信令数据与地理信息区块绑定,根据时间特征和地理区块的社会属性,识别居民的基本职住娱信息;然后综合民生POI点、出行特征拓展关键词、图谱等多源数据,运用工作日通勤分析模型和节假日出行特征提取模型,识别用户的通勤距离、通勤方式、日均通勤频次、周均工作时长、节假日出行场景、出行频次、驻留时长等内容,并形成涵盖职住娱信息的出行特征类标签集。以成都市为例,采集连续1个月的手机信令数据和同时期的POI等数据,验证了该方法的可行性,该成果作为反映城市实际人口规模数量和空间分布特征的城市人口地图大数据产品的重要内容,为政府部门、商企用户开展相关分析业务提供数据支撑。     

Multi-Scale Visualisation of Inbound and Outbound Traffic Delays in London

Abstract

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Traffic delays can be used to quantify traffic congestion on the road. However, traffic delay data itself cannot provide readily useful content about congestion directly. The aim of this research is to develop a multi-scale visualisation of traffic delay (excess travel time in minutes per kilometre) derived from automatic number plate reading (ANPR) data, to enable traffic commuting patterns to and from Central London to be understood and analysed further.     

Mapping hourly dynamics of urban population using trajectories reconstructed from mobile phone records

Understanding the spatiotemporal dynamics of urban population is crucial for addressing a wide range of urban planning and management issues. Aggregated geospatial big data have been widely used to quantitatively estimate population distribution at fine spatial scales over a given time period. However, it is still a challenge to estimate population density at a fine temporal resolution over a large geographical space, mainly due to the temporal asynchrony of population movement and the challenges to acquiring a complete individual movement record. In this article, we propose a method to estimate hourly population density by examining the time‐series individual trajectories, which were reconstructed from call detail records using BP neural networks. We first used BP neural networks to predict the positions of mobile phone users at an hourly interval and then estimated the hourly population density using log‐linear regression at the cell tower level. The estimated population density is linearly correlated with population census data at the sub‐district level. Trajectory clustering results show five distinct diurnal dynamic patterns of population movement in the study area, revealing spatially explicit characteristics of the diurnal commuting flows, though the driving forces of the flows need further investigation.     

The utility of travelling when destinations are heterogeneous. How much better is the next destination as one travels further?

In many studies travel behaviour (for example, commuting) is analysed on the basis of a utility function with the distance (d) travelled as one of the arguments. An example is U=U(d,Y-cd,T-td) where Y and T denote money and time constraints, and c and t money and time costs per unit distance. This standard approach is not without problems, however, since it ignores the fundamental fact that most transport has a derived character: travelling kilometres is not an activity that gives utility per se, but only because these kilometres bring people to certain places they want to visit. In this paper we develop a method that provides a justification for utility functions such as shown here by showing that these can be made consistent with theories that take into account the derived character of transport.     

Modeling commuting patterns in a multi-regional input–output framework: impacts of an ‘urban re-centralization’ scenario

The paper suggests a modeling approach for assessing economic and social impacts of changes in urban forms and commuting patterns that extends a multi-regional input–output framework by incorporating a set of commuting-related consequences. The Lisbon Metropolitan Area case with an urban re-centralization scenario is used as an example to illustrate the relevance of this modeling approach for analyzing commuting-related changes in regional income distribution on the one side and in household consumption structures on the other.     

基于超图的拨地信息管理系统的设计与实现

本文阐述了如何利用超图开发平台、VB编程语言、SQL Server2000开发拨地管理系统的方法,同时结合拨地信息管理系统阐明了地理信息系统的基本功能和开发技术。     

基于GPS/INS的影像实时定位与误差分析

遥感影像目标实时定位的关键是外方位元素的实时获取,在航空遥感平台上加载GPS/INS组合导航系统能够满足这一需求.文中首先给出了基于GPS/INS系统的目标直接定位方法;然后从摄影测量的角度,重点推导了影像内外方位元素对目标定位的误差传递公式;并运用实例验证了公式的有效性.     

TAZ-level variation in work trip mode choice between 1990 and 2000 and the presence of rail transit

Rail transit continues to be a popular alternative for cities as a tool for alleviating automobile congestion and for redeveloping areas into transit and pedestrian-friendly environments. Ideally, rail transit will draw trips away from cars, but the quantitative work that tests this notion has often been either case studies of neighborhoods, in which conclusions are tough to generalize, or citywide comparisons where important spatial variation is lost in aggregation. This study seeks to narrow this gap in the research by using multivariate analysis of covariance to isolate the effect of covariates and cities on changes in work trip mode choice at the traffic analysis zone (TAZ) level for nine cities between 1990 and 2000. The results suggest differences by city in the change at the TAZ level of the proportion of people driving alone and taking transit. Increases in transit usage were associated with cities that built rail transit, while increases in automobile commuting and decreases in transit usage were associated with cities that did not.     

基于GPS/INS的影像实时定位与误差分析

遥感影像目标实时定位的关键是外方位元素的实时获取,在航空遥感平台上加载GPS/INS组合导航系统能够满足这一需求。文中首先给出了基于GPS/INS系统的目标直接定位方法;然后从摄影测量的角度,重点推导了影像内外方位元素对目标定位的误差传递公式;并运用实例验证了公式的有效性。     

水库测绘信息系统的设计与实现

水库中测量数据的采集方式已经发生改变,效率大大提高,但是数据管理和处理方式仍然滞后,特别对于冲刷淤积等计算主要还是依赖于人工进行计算,这样处理费时费力而且容易出错。为了改变这种状况,作者选用GIS组件技术和高级开发语言Visual C++开发了水库测绘信息系统,实现了对水库测量数据的有效管理和处理自动化。首先论述了系统的设计目标和开发技术,然后再详细阐述了系统各模块的功能和系统实现的关键技术。     

基于GIS的区域经济统计分析系统的设计与实现

随着经济的发展,区域间经济相互作用和影响的关系越来越密切,忽略空间相互作用的传统区域经济分析手段和方法开始显现出一些明显的不足。而GIS在处理和分析区域地理数据上具有强大的空间分析能力,为此我们引入GIS工具对区域经济进行分析,相较于传统的分析手法有了很大改善。本文以江西省区域经济数据为例,设计了一个基于GIS的区域经济统计分析系统,并利用Arcob-jects二次开发控件结合VB可视化编程语言,实现了大部分区域经济统计分析功能,最后并将结果进行网络发布。研究结果表明将GIS引入到区域经济统计分析中,更能正确、有效的揭示区域经济发展在空间上的联系,为区域经济研究决策提供服务。     

两种地心参考系的惯性性质及比较

本文讨论了地心恒星参考系和地心本征参考系的惯性性质,指出在距离地心160公里范围之外的空间,地心恒星参考系的惯性性质优于地心本征参考系。然而,为了研究人造卫星系统内部的某些效应,则以建立原点位于人造卫星质心的卫星本征参考系为佳。     

An Agricultural Monitoring System Based on the Use of Remotely Sensed Imagery and Field Server Web Camera Data

In this study, the authors develop an integrated agricultural monitoring system based on the use of high-spatial-resolution remote sensing imagery and Field Server data for a cabbage field in Tsumagoi, Gunma Prefecture, Japan. The use of the integrated system made it possible to verify the accuracy of cabbage coverage estimated from high-spatial-resolution QuickBird imagery using an unmixing method, because the authors were able to remotely examine cabbages growing in real-time using a Field Server web camera linked to their laboratory via the Internet. Using the developed integrated system, they produced a cabbage coverage map that provided information on cabbage growth that could be used for agricultural land management, particularly with regard to the application of fertilizer and forecasting crop production. The results support the validity of using remote sensing technology in conjunction with a Field Server to manage agricultural crop land.     

Understanding the interplay between bus,metro, and cab ridership dynamics in Shenzhen,China

The most common mass transit modes in metropolitan cities include buses, subways, and taxicabs, each of which contribute to an interconnected complex network that delivers urban dwellers to their destinations. Understanding the intertwined usages of these three transit modes at different places and time allows for better sensing of urban mobility and the built environment. In this article, we leverage a comprehensive data collection of bus, metro, and taxicab ridership from Shenzhen, China to unveil the spatio‐temporal interplay between different mass transit modes. To achieve this goal, we develop a novel spectral clustering framework that imposes spatio‐temporal similarities between mass transit mode usage in urban space and differentiates urban spaces associated with distinct ridership patterns of mass transit modes. Five resulting categories of urban spaces are identified and interpreted with auxiliary knowledge of the city's metro network and land‐use functionality. In general, different categorized urban spaces are associated with different accessibility levels (such as high‐, medium‐, and low‐ranked) and different urban functionalities (such as residential, commercial, leisure‐dominant, and home–work balanced). The results indicate that different mass transit modes cooperate or compete based on demographic and socioeconomic attributes of the underlying urban environments. Our proposed analytical framework provides a novel and effective way to explore the mass transit system and the functional heterogeneity in cities. It demonstrates great potential for assisting policymakers and municipal managers in optimizing public transportation facility allocation and city‐wide daily commuting distribution.     

Interpolating Spatial Interaction Data1

Spatial interpolation has been widely used to improve the spatial granularity of data, or to mediate between inconsistent zoning schemes of spatial data. Traditional areal interpolation methods translate values of source zones to those of target zones. These methods have difficulty in dealing with flow data, as each instance is associated with a pair of zones. This study develops a new concept, flow line interpolation, to fill the abovementioned gap. We also develop a first flow line interpolation method to estimate commuting flow data between spatial units in a target zoning scheme based on such data in a source zoning scheme. Three models (i.e., areal‐weighted, intelligent, and gravity‐type flow line interpolation) are presented. To test the estimation accuracy and the application potential of these models, a case study of Fulton County in Georgia is conducted. The results reveal that both the areal‐weighted and intelligent models are very promising flow line interpolation methods.     

地理信息服务中数据传输性能分析

地理信息服务系统具有数据密集型和计算密集型的特点,对网络环境的设置有着特殊的需求。本文从地理信息服务系统中对数据传输应用的角度出发,从网络数据传输协议的传输层和应用层两个层次分析地理信息服务系统应用的特殊性,并根据系统应用的特殊需求提出相应的解决方案,提高整个应用系统中各类数据传输的效率、性能和系统运行的稳定性,提高地理信息服务系统为多用户提供地图服务、位置服务以及各种应用服务的综合能力。提高系统适应多用户并发访问海量数据的地图服务作业和频繁访问实效性很强的位置服务作业的能力。     

DESIGN AND REALIZATION OF MAP DIGITIZATION SYSTEM ON MICRO-COMPUTER BASED MAP GRAPHIC WORKSTATION

The main purpose to develop a Map Graphic Workstation on thewidely used micro-computer is that by it the whole processing of map data fromcapturing,managing,editing,updating to graphic outputting can be realized.Map Digitization System（MDS）is the software system to deal with the initial andalso the most important processing.In this paper,the authors introduce a MDSon a micro-computer based Map Grphic Workstation that has been qualitified forthe producation of digital map.Since the system is designed totally independentlyand in the general frame of the Map Graphic Workstation,the capturing and man-aging and other processings for map data are in an integral manner,in which theproducation of digital map can be fulfilled conveniently.At the same time,thesystem is flexible for function extension and widely applicable to the data from dif-ferent sources and with different information characterisitcs(e.g.,the processingof Chinese characters on map).     

机载激光雷达点云数据的实时渲染

提出了一种实时绘制大规模LIDAR点云数据的方法。该方法通过构建一棵顺序四叉树使点云均匀分布在四叉树节点上,来实现快速的数据筛选。阐述了顺序四叉树的快速建立,并通过一个试验系统验证了文中所提方法的有效性。试验表明,使用目前普通配置的计算机,通过自适应控制绘制的数据量,可以实时绘制约1GB的原始点云数据。     

Equal-Area Projections of the Triaxial Ellipsoid: First Time Derivation and Implementation of Cylindrical and Azimuthal Projections for Small Solar System Bodies

Many small solar system bodies such as asteroids or small satellites have irregular shapes, often approximated by the reference surface of a triaxial ellipsoid. Map projections for the triaxial ellipsoid are needed to present the incoming data in the form of maps. In this paper the formulae of equal-area cylindrical and azimuthal projections of the triaxial ellipsoid were derived and practically implemented for the first time using as an example the asteroid 253 Mathilde. This paper is the final in a series of papers devoted to all main classes of projections of the triaxial ellipsoid. Before this, the authors obtained equidistant along meridians projection and Jacobi conformal projection for the triaxial ellipsoid.