共查询到20条相似文献，搜索用时 140 毫秒
1.
Karl Rehrl Simon Gröchenig Stefan Kranzinger 《International journal of geographical information science》2020,34(10):1953-1979
ABSTRACT Trajectory data mining is a lively research field in the domain of spatio-temporal data mining. Trajectory pattern mining comprises a set of specific pattern mining methods, which are applied as consecutive steps on a trajectory with the goal to extract and classify re-occurring spatio-temporal patterns. Despite the common nature and frequent usage of such methods by the GIScience community, a methodological approach is missing so far, especially when it comes to the use of machine learning-based classification methods. The current work closes this gap by proposing and evaluating a machine learning-based 3-steps trajectory data mining methodology using the detection and classification of stop points in vehicle trajectories as example. The work describes in detail the applied methodologies with respect to the three mining steps ‘stop detection’, ‘feature extraction’ and ‘classification in traffic-relevant and non-traffic-relevant stops’ and evaluates six machine learning-based classification algorithms using a real-world dataset of 15,498 vehicle trajectories with 5,899 detected stops (thereof 2,032 manually classified). Due to its exemplary nature, the presented methodology is suited to act as blueprint for similar trajectory data mining problems. 相似文献
2.
R. Ahas A. Aasa Y. Yuan M. Raubal Z. Smoreda Y. Liu 《International journal of geographical information science》2015,29(11):2017-2039
This paper proposes a methodology for using mobile telephone-based sensor data for detecting spatial and temporal differences in everyday activities in cities. Mobile telephone-based sensor data has great applicability in developing urban monitoring tools and smart city solutions. The paper outlines methods for delineating indicator points of temporal events referenced as ‘midnight’, ‘morning start’, ‘midday’, and ‘duration of day’, which represent the mobile telephone usage of residents (what we call social time) rather than solar or standard time. Density maps by time quartiles were also utilized to test the versatility of this methodology and to analyze the spatial differences in cities. The methodology was tested with data from cities of Harbin (China), Paris (France), and Tallinn (Estonia). Results show that the developed methods have potential for measuring the distribution of temporal activities in cities and monitoring urban changes with georeferenced mobile phone data. 相似文献
3.
Qunying Huang 《International journal of geographical information science》2017,31(3):523-541
Social media applications are widely deployed in mobile platforms equipped with built-in GPS tracking devices, and these devices have led to an unprecedented collection of geolocated data (geo-tags). Geo-tags, along with place names, offer new opportunities to explore the trajectory and mobility patterns of social media users. However, trajectory data captured by social media are sparsely and irregularly spaced and therefore have varying degrees of resolution in both space and time. Previous studies on next location prediction are mostly applicable for detecting the upcoming location of a moving object using dense GPS trajectories where locations are recorded at regular time intervals (e.g., 1 minute). Additionally, point features are commonly used to represent the locations of visits, but using point features cannot capture the variability of human mobility. This article introduces a new methodology to predict an individual’s next location based on sparse footprints accumulated over a long time period using social networks, and uses polygons to represent the location corresponding to the physical activity area of individuals. First, the density-based spatial clustering algorithm is employed to discover the most representative activity zones that an individual frequently visits on a daily basis, and a polygon-based region is then derived for each representative activity zone. A sparse mobility Markov chain model considering both the movements and online behaviors of the social media user is trained and used to predict the user’s next location. Initial experiments with a group of Washington DC Twitter users demonstrate that the proposed methodology successfully discovers the activity regions and predicts the user’s next location with accuracy approaching 78.94%. 相似文献
4.
人类活动轨迹的分类、模式和应用研究综述 总被引：4，自引：3，他引：1
各种传感器的应用与发展,如车载GPS、手机、公交卡、银行卡等,记录了人类的活动轨迹。这些海量的人类活动轨迹数据中蕴含着人类行为的时空分布模式。通过对这些轨迹的研究可以挖掘个体轨迹模式,理解人类动力学特征,进而为对轨迹预测、城市规划、交通监测等提供支持。因此,研究各类传感器记录的人类活动轨迹数据成为当前的研究热点。本文对人类活动轨迹的获取与表达方式进行剖析,并将人类的活动轨迹按照采样方式和驱动因素的不同分为基于时间间隔采样、基于位置采样和基于事件触发采样等3类轨迹数据。由于各类轨迹数据均由起始点、锚点和一般节点等构成,因而将轨迹模式挖掘的研究按照锚点、出行范围、形状模式、OD流模式、时间模式等进行组织,研究成果揭示人类活动轨迹在时间、空间的从聚模式、周期性等特点。在此基础上,将人类活动轨迹在城市研究中的应用,按照用户轨迹预测、城市动态景观、城市交通模拟与监控、城市功能单元识别以及城市中其他方面的研究应用进行系统综述,认为人类活动模式挖掘是城市规划、城市交通、公共安全等方面应用的基础。 相似文献
5.
以上海市青浦区为例,采用数据包络模型、空间自相关模型、多元Logistic回归模型、地理探测器和层次聚类模型分析该区184个行政村社会?生态系统脆弱性的空间差异及地理影响机制。研究表明：① 基于熵权集结交叉的“投入?产出”效率模型对村域社会?生态系统脆弱性评价结果更具可信度和精确性,2018年行政村社会?生态系统脆弱性空间上呈由东向西逐渐降低的变化趋势,脆弱性均值为0.583;② 地理因素对经济发达村域社会?生态系统脆弱性空间分异仍旧具有重要影响。距上海市中心距离、距淀山湖距离、距青浦区中心距离和水域面积成为影响该区社会?生态系统脆弱性的4种主导地理因素,其地理影响力呈现系统结构空间差异和种类属性替代及程度转化;③ 依据地理因素影响力聚类分析将该区社会?生态系统脆弱性地理因素空间耦合模式分为10种,多地理因素耦合模式是主要决定类型,呈现中部多因素主导和两侧单因素主导并存的多元环状地域决定格局;针对不同类型提出调控区域社会?生态系统脆弱性的可行方式。 相似文献
6.
Hai Huang 《International journal of geographical information science》2013,27(12):2075-2094
This paper presents an original approach to dynamic anomalous behavior detection in individual trajectory using a recursive Bayesian filter. The anomalous pattern detection is of great interest for navigation, driver assistance systems, surveillance as well as crisis management. In this work, we focus on the GPS trajectories of automobiles finding where the driver’s behavior shows anomalies. Such anomalous behaviors can happen in many cases, especially when the driver encounters orientation problems, i.e., taking a wrong turn, performing a detour, or losing the way. First, three high-level features, i.e., turns and their density, detour factor, and route repetition are extracted from the given trajectory geometry, for which a long-term perspective is required to observe data sequences of a significant length instead of individual time stamps. We therefore employ high-order Markov chains with a ‘dynamic memory’ to model the trajectory integrating these long-term features. The Markov model is processed by a proposed recursive Bayesian filter to infer an optimal probability distribution of the potential anomalous driving behaviors dynamically over time. The filter performs unsupervised detection in single trajectories based on local features only. No training process is required to characterize the anomalous behaviors. By analyzing the detection results of individual trajectories, collective behaviors can be derived indicating traffic issues such as congestions and turn restrictions. Experiments are performed on volunteered geographic information (VGI) data, self-acquired trajectories, and open trajectory datasets to demonstrate the potential of the proposed approach. 相似文献
7.
Min Cao Quanfei Shen Yanxia Wang 《International journal of geographical information science》2013,27(5):806-824
This paper presents an intelligent approach to discover transition rules for cellular automata (CA) by using cuckoo search (CS) algorithm. CS algorithm is a novel evolutionary search algorithm for solving optimization problems by simulating breeding behavior of parasitic cuckoos. Each cuckoo searches the best upper and lower thresholds for each attribute as a zone. When the zones of all attributes are connected by the operator ‘And’ and linked with a cell status value, one CS-based transition rule is formed by using the explicit expression of ‘if-then’. With two distinct advantages of efficient random walk of Lévy flights and balanced mixing, CS algorithm performs well in both local search and guaranteed global convergence. Furthermore, the CA model with transition rules derived by CS algorithm (CS-CA) has been applied to simulate the urban expansion of Nanjing City, China. The simulation produces encouraging results, in terms of numeric accuracy and spatial distribution, in agreement with the actual patterns. Preliminary results suggest that this CS approach is well suitable for discovering reliable transition rules. The model validation and comparison show that the CS-CA model gets a higher accuracy than NULL, BCO-CA, PSO-CA, and ACO-CA models. Simulation results demonstrate the feasibility and practicability of applying CS algorithm to discover transition rules of CA for simulating geographical systems. 相似文献
8.
Min Deng Jincai Huang Huimin Liu Luliang Tang Jianbo Tang 《International journal of geographical information science》2018,32(12):2337-2361
Detailed real-time road data are an important prerequisite for navigation and intelligent transportation systems. As accident-prone areas, road intersections play a critical role in route guidance and traffic management. Ubiquitous trajectory data have led to a recent surge in road map reconstruction. However, it is still challenging to automatically generate detailed structural models for road intersections, especially from low-frequency trajectory data. We propose a novel three-step approach to extract the structural and semantic information of road intersections from low-frequency trajectories. The spatial coverage of road intersections is first detected based on hotspot analysis and triangulation-based point clustering. Next, an improved hierarchical trajectory clustering algorithm is designed to adaptively extract the turning modes and traffic rules of road intersections. Finally, structural models are generated via K-segment fitting and common subsequence merging. Experimental results demonstrate that the proposed method can efficiently handle low-frequency, unstable trajectory data and accurately extract the structural and semantic features of road intersections. Therefore, the proposed method provides a promising solution for enriching and updating routable road data. 相似文献
9.
Yizhuo Li Fan Zhang 《International journal of geographical information science》2013,27(12):2385-2405
ABSTRACTRegionalization attempts to group units into a few subsets to partition the entire area. The results represent the underlying spatial structure and facilitate decision-making. Massive amounts of trajectories produced in the urban space provide a new opportunity for regionalization from human mobility. This paper proposes and applies a novel regionalization method to cluster similar areal units and visualize the spatial structure by considering all trajectories in an area into a word embedding model. In this model, nodes in a trajectory are regarded as words in a sentence, and nodes can be clustered in the feature space. The result depicts the underlying socio-economic structure at multiple spatial scales. To our knowledge, this is the first regionalization method from trajectories with natural language processing technology. A case study of mobile phone trajectory data in Beijing is used to validate our method, and then we evaluate its performance by predicting the next location of an individual’s trajectory. The case study indicates that the method is fast, flexible and scalable to large trajectory datasets, and moreover, represents the structure of trajectory more effectively. 相似文献
10.
通过爬取GPS轨迹记录平台的轨迹数据,采用季节强度指数、核密度分析、近邻分析等方法对山东长岛游客时空行为进行相似性探讨,研究表明：① 年内,在气候要素影响下,海岛型目的地季节强度指数更高;日内,轨迹数量的“双峰”结构和轨迹长度的“三峰”结构都表明游客出行时间和轨迹长度有强相似性和集中性,且行程结束时间相对更晚;② 空间上,交通的不可直达性和时间的限制性造成游客在岛屿选择上高度集中,空间轨迹相似度很高,呈现典型的“轴状”和“环状”集聚结构,“向海”和“亲海”特征突出;③ 游客在海岛上的流动形成典型的等级分层结构和节点分散分布特征,重要节点对旅游流网络的控制作用明显;④ 与其他类型目的地相比,景区的核心作用在海岛上不够突出,受景区进入率不高的影响,游客在旺季期间与本地居民在公共交通设施和公共休闲空间的使用上重叠率较高,是造成旅游旺季部分路段和休闲空间过度拥挤的核心原因。 相似文献
11.
THE 'LITTLE ICE AGE': RE-EVALUATION OF AN EVOLVING CONCEPT 总被引：4，自引：0，他引：4
JOHN A. MATTHEWS KEITH R. BRIFFA 《Geografiska Annaler: Series A, Physical Geography》2005,87(1):17-36
ABSTRACT. This review focuses on the development of the ‘Little Ice Age’ as a glaciological and climatic concept, and evaluates its current usefulness in the light of new data on the glacier and climatic variations of the last millennium and of the Holocene. ‘Little Ice Age’ glacierization occurred over about 650 years and can be defined most precisely in the European Alps (c. AD 1300–1950) when extended glaciers were larger than before or since. ‘Little Ice Age’ climate is defined as a shorter time interval of about 330 years (c. AD 1570–1900) when Northern Hemisphere summer temperatures (land areas north of 20°N) fell significantly below the AD 1961–1990 mean. This climatic definition overlaps the times when the Alpine glaciers attained their latest two highstands (AD 1650 and 1850). It is emphasized, however, that ‘Little Ice Age’ glacierization was highly dependent on winter precipitation and that ‘Little Ice Age’ climate was not simply a matter of summer temperatures. Both the glacier‐centred and the climate‐centred concepts necessarily encompass considerable spatial and temporal variability, which are investigated using maps of mean summer temperature variations over the Northern Hemisphere at 30‐year intervals from AD 1571 to 1900. ‘Little Ice Age’‐type events occurred earlier in the Holocene as exemplified by at least seven glacier expansion episodes that have been identified in southern Norway. Such events provide a broader context and renewed relevance for the ‘Little Ice Age’, which may be viewed as a ‘modern analogue’ for the earlier events; and the likelihood that similar events will occur in the future has implications for climatic change in the twenty‐first century. It is concluded that the concept of a ‘Little Ice Age’ will remain useful only by (1) continuing to incorporate the temporal and spatial complexities of glacier and climatic variations as they become better known, and (2) by reflecting improved understanding of the Earth‐atmosphere‐ocean system and its forcing factors through the interaction of palaeoclimatic reconstruction with climate modelling. 相似文献
12.
江汉平原乡村聚落形态类型及空间体系特征 总被引：3，自引：0，他引：3
依据国土空间用地GIS数据及村镇统计数据,采用聚类分析及分形学方法,探索江汉平原乡村聚落空间形态类型及空间体系特征。研究表明,江汉平原因其内部自然环境基质的差异,形成了“二类四型”聚落空间形态:低丘岗地地域,主要是均衡镶嵌型聚落空间形态,可分为高密度（斑块）低丘点状形态及中密度（斑块）岗地团块形态2种亚型,此类聚落形态的村镇呈现出“星点”式空间结构;河渠水网地域,主要是轴带依附型聚落空间形态,可分为低密度（斑块）滨湖弧带形态和中低密度（斑块）河渠直线形态2种亚型,此类聚落形态的村镇呈现“点轴”式空间结构。江汉平原“二类四型”乡村聚落形态及空间体系结构在长江中游平原水网农区有一定的典型性,可以为此类乡村聚落空间重构、乡村居民点体系优化提供理论基础及实践指导。 相似文献
13.
Dr Helen Mounsey 《International journal of geographical information science》2013,27(3):259-261
Spatial data uncertainty models (SDUM) are necessary tools that quantify the reliability of results from geographical information system (GIS) applications. One technique used by SDUM is Monte Carlo simulation, a technique that quantifies spatial data and application uncertainty by determining the possible range of application results. A complete Monte Carlo SDUM for generalized continuous surfaces typically has three components: an error magnitude model, a spatial statistical model defining error shapes, and a heuristic that creates multiple realizations of error fields added to the generalized elevation map. This paper introduces a spatial statistical model that represents multiple statistics simultaneously and weighted against each other. This paper's case study builds a SDUM for a digital elevation model (DEM). The case study accounts for relevant shape patterns in elevation errors by reintroducing specific topological shapes, such as ridges and valleys, in appropriate localized positions. The spatial statistical model also minimizes topological artefacts, such as cells without outward drainage and inappropriate gradient distributions, which are frequent problems with random field-based SDUM. Multiple weighted spatial statistics enable two conflicting SDUM philosophies to co-exist. The two philosophies are ‘errors are only measured from higher quality data’ and ‘SDUM need to model reality’. This article uses an automatic parameter fitting random field model to initialize Monte Carlo input realizations followed by an inter-map cell-swapping heuristic to adjust the realizations to fit multiple spatial statistics. The inter-map cell-swapping heuristic allows spatial data uncertainty modelers to choose the appropriate probability model and weighted multiple spatial statistics which best represent errors caused by map generalization. This article also presents a lag-based measure to better represent gradient within a SDUM. This article covers the inter-map cell-swapping heuristic as well as both probability and spatial statistical models in detail. 相似文献
14.
The damage of dwelling houses constitutes the primary cause of casualties and asset loss in seismic disasters that occurred in Chinese rural areas. The structure of houses is crucial for assessing the vulnerability of rural houses. However, at present, available data on rural housing structure are incomplete and their spatial scales are inconsistent. This paper estimated the amount and ratio of rural houses in five structures, namely ’wood’, ’brick’, ’mixed’, ’reinforced concrete’, and ’other’, for 2380 counties across China. With the percent-age sampling census data in 2005, four accuracy levels were specified. Then, a set of down-scaling models were established, where the impact of climate, economic development level and ethnic minority cultural factors on rural housing structure, as well as the spatial autocorrelation of neighboring spatial units were considered. Based on the estimation results, a database of county-level rural housing structure was established, based on which the vul-nerability of rural houses in different areas was clarified. 相似文献
15.
16.
Xiaohua Tong 《International journal of geographical information science》2020,34(5):866-898
ABSTRACT Cellular automata (CA) models are in growing use for land-use change simulation and future scenario prediction. It is necessary to conduct model assessment that reports the quality of simulation results and how well the models reproduce reliable spatial patterns. Here, we review 347 CA articles published during 1999–2018 identified by a Scholar Google search using ‘cellular automata’, ‘land’ and ‘urban’ as keywords. Our review demonstrates that, during the past two decades, 89% of the publications include model assessment related to dataset, procedure and result using more than ten different methods. Among all methods, cell-by-cell comparison and landscape analysis were most frequently applied in the CA model assessment; specifically, overall accuracy and standard Kappa coefficient respectively rank first and second among all metrics. The end-state assessment is often criticized by modelers because it cannot adequately reflect the modeling ability of CA models. We provide five suggestions to the method selection, aiming to offer a background framework for future method choices as well as urging to focus on the assessment of input data and error propagation, procedure, quantitative and spatial change, and the impact of driving factors. 相似文献
17.
Jianming Liang Wenhang Li Abdoul Nasser Ibrahim 《International journal of geographical information science》2014,28(4):780-798
The temporal and spatial distribution of solar energy in urban areas is highly variable because of the complex building structures present. Traditional GIS-based solar radiation models rely on two-dimensional (2D) digital elevation models to calculate insolation, without considering building facades and complicated three-dimensional (3D) shading effects. Inspired by the ‘texture baking’ technique used in computer graphics, we propose a full 3D method for computing and visualizing urban solar radiation based on image-space data representation. First, a surface mapping approach is employed to project each 3D triangular mesh onto a 2D raster surface whose cell size determines the calculation accuracy. Second, the positions and surface normal vectors of each 3D triangular mesh are rasterized onto the associated 2D raster using barycentric interpolation techniques. An efficient compute unified device architecture -accelerated shadow-casting algorithm is presented to accurately capture shading effects for large-scale 3D urban models. Solar radiation is calculated for each raster cell based on the input raster layers containing such information as slope, aspect, and shadow masks. Finally, a resulting insolation raster layer is produced for each triangular mesh and is represented as an RGB texture map using a color ramp. Because a virtual city can be composed of tens of thousands of triangular meshes and texture maps, a texture atlas technique is presented to merge thousands of small images into a single large image to batch draw calls and thereby efficiently render a large number of textured meshes on the graphics processing unit. 相似文献
18.
19.
《Norsk geografisk tidsskrift. Norwegian journal of geography》2012,66(4):148-156
A small-scale land resource map was compiled by combining generalised large-scale maps with auxiliary data and interpreted satellite images. The large-scale maps covered areas below the treeline and were generalised using an expansion-contraction algorithm (ECA). Areas above the treeline were added by manual interpretation of a Landsat TM image (Band 4,5,3). Certain features were also copied from small-scale topographic maps. The thematic accuracy was evaluated individually for different segments of the map, according to the production technique. The general accuracy was satisfactory in areas where the ECA technique had been applied. Areas mapped using auxiliary data were rendered inaccurately both below and above the treeline, but the result was still found acceptable. The results from satellite interpretation above the treeline were promising, but need to be improved. The image interpretation can either be refined by using alternative sensors, by improved training of the interpreters, or by adjusting the definition of the land resource classes in order to attain a better match between the class definitions and the result of the classification. 相似文献
20.
基于居住适宜性的农村居民点空间重构类型识别——以陇中黄土丘陵区魏店镇为例 总被引：1，自引：0，他引：1
以陇中黄土丘陵区魏店镇为研究对象,基于村庄详细调查数据库,在农村居民点空间布局形态分析的基础上,构建乡村“基础生活圈”和布局适宜性评价指标体系,识别农村居民点空间重构类型并提出应对策略。结果表明：① 魏店镇农村居民点受自然禀赋和交通因素的影响,呈现出“集中为主、分散为辅、散中有聚”的空间布局特征,且景观分异明显;② 10和20 min生活圈内覆盖的居民点面积和数量差异较大,相对集聚状态下的居民点更容易获得公共服务设施;③ 农村居民点布局适宜程度较好,以中、高度适宜为主,二者斑块数量达到1742个,占到所有居民点总数的85.18%;④ 运用空间错位分析的二维组合矩阵将农村居民点“基础生活圈”和布局适宜性评价相叠加,重构为集聚提升型、引导发展型和搬迁扶持型。 相似文献