Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems最新文献

Efficient representation and analysis of triangulated terrains 三角地形的有效表示和分析

Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems Pub Date : 2017-11-07 DOI: 10.1145/3139958.3140050

Riccardo Fellegara, F. Iuricich, L. Floriani

引用次数: 6

Spatio-Temporal Join on Apache Spark Apache Spark上的时空连接

Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems Pub Date : 2017-11-07 DOI: 10.1145/3139958.3139963

Randall T. Whitman, Michael B. Park, Bryan G. Marsh, E. Hoel

{"title":"Spatio-Temporal Join on Apache Spark","authors":"Randall T. Whitman, Michael B. Park, Bryan G. Marsh, E. Hoel","doi":"10.1145/3139958.3139963","DOIUrl":"https://doi.org/10.1145/3139958.3139963","url":null,"abstract":"Effective processing of extremely large volumes of spatial data has led to many organizations employing distributed processing frameworks. Apache Spark is one such open-source framework that is enjoying widespread adoption. Within this data space, it is important to note that most of the observational data (i.e., data collected by sensors, either moving or stationary) has a temporal component, or timestamp. In order to perform advanced analytics and gain insights, the temporal component becomes equally important as the spatial and attribute components. In this paper, we detail several variants of a spatial join operation that addresses both spatial, temporal, and attribute-based joins. Our spatial join technique differs from other approaches in that it combines spatial, temporal, and attribute predicates in the join operator. In addition, our spatio-temporal join algorithm and implementation differs from others in that it runs in commercial off-the-shelf (COTS) application. The users of this functionality are assumed to be GIS analysts with little if any knowledge of the implementation details of spatio-temporal joins or distributed processing. They are comfortable using simple tools that do not provide the ability to tweak the configuration of the","PeriodicalId":270649,"journal":{"name":"Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123551119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

A Linear-Time Algorithm for the Aggregation and Visualization of Big Spatial Point Data 空间大点数据聚合与可视化的线性时间算法

Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems Pub Date : 2017-11-07 DOI: 10.1145/3139958.3140037

Christian Beilschmidt, T. Fober, Michael Mattig, B. Seeger

引用次数: 7

How "Alternative" are Alternative Facts?: Towards Measuring Statement Coherence via Spatial Analysis 另类事实是如何“另类”的?论空间分析对语句连贯性的测量

Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems Pub Date : 2017-11-07 DOI: 10.1145/3139958.3140058

K. Janowicz, Grant McKenzie

{"title":"How \"Alternative\" are Alternative Facts?: Towards Measuring Statement Coherence via Spatial Analysis","authors":"K. Janowicz, Grant McKenzie","doi":"10.1145/3139958.3140058","DOIUrl":"https://doi.org/10.1145/3139958.3140058","url":null,"abstract":"Following the AAA principle by which anybody can say anything about any topic, the Web is no stranger to alternative facts. Nonetheless, with the increasing volume and velocity at which content is being published and difficulties to assess the credibility of information and the trustworthiness of sources, alternative facts are becoming a major challenge and an instrument for spreading disinformation. Interestingly, the diversity of today's data sources can also help us to counter alternative facts by measuring their coherence, i.e., the degree to which data from one source confirms or contradict data from another source. While a single dataset can be biased towards supporting or discrediting a statement, the diverse sources of data across media types that are publicly accessible today offer unique perspectives on which to assess a given statement. To give an intuitive example, a statement about the comparison of crowd sizes should align with photos of said crowds. However, these photos could be taken at different times, from different viewpoints, and could lead to different, sample-based estimations. Adding further data from heterogeneous sources, such as metro ridership, can either further support a statement or contradict it. We use three thought experiments to discuss the role of geographic data, knowledge graphs, and spatial analysis in approaching alternative facts from a novel angle, namely by studying their coherence, i.e., whether they align with other statements, instead of trying to falsify them. In doing so, we aim at increasing the costs for maintaining alternative facts.","PeriodicalId":270649,"journal":{"name":"Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129573856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

BESTED: An Exponentially Smoothed Spatial Bayesian Analysis Model for Spatio-temporal Prediction of Daily Precipitation 日降水时空预测的指数平滑空间贝叶斯分析模型

Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems Pub Date : 2017-11-07 DOI: 10.1145/3139958.3140040

Monidipa Das, S. Ghosh

引用次数: 8

Efficient Processing of Reachability Queries with Meetings 会议可达性查询的有效处理

Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems Pub Date : 2017-11-07 DOI: 10.1145/3139958.3139982

Elena V. Strzheletska, V. Tsotras

{"title":"Efficient Processing of Reachability Queries with Meetings","authors":"Elena V. Strzheletska, V. Tsotras","doi":"10.1145/3139958.3139982","DOIUrl":"https://doi.org/10.1145/3139958.3139982","url":null,"abstract":"The prevalence of location tracking systems has resulted in large volumes of spatiotemporal data generated every day. Addressing reachability queries on such datasets is important for a wide range of applications, such as security monitoring, surveillance, public health, epidemiology, social networks, etc. Given two objects OS, OT and a time interval I, a reachability query identifies whether information (or physical items etc.) could have transferred from OS to OT during I (typically indirectly through intermediaries). While traditional graph reachability queries have been studied extensively, little work exists on processing spatiotemporal reachability queries for large disk-resident trajectory datasets. Moreover, previous research assumed that information can be passed from one object to another instantaneously. However, in many applications such transfer takes time (i.e., a short conversation), thus forcing interacting objects to stay in contact for some time interval. This requirement makes the query processing even more challenging. In this paper, we introduce a novel problem, namely, spatiotemporal reachability queries with meetings and propose two algorithms, RICCmeetMin and RICCmeetMax. To prune the search space during query time, these algorithms precompute some reachability events: the shortest valid meetings (RICCmeetMin), and the longest possible meetings (RICCmeetMax) respectively. An extended experimental evaluation examines the efficiency and pruning characteristics of both algorithms over a variety of spatiotemporal reachability queries with meetings on large disk-resident datasets.","PeriodicalId":270649,"journal":{"name":"Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128345440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Sampling Frequency Effects on Trajectory Routes and Road Network Travel Time 采样频率对轨迹路线和路网运行时间的影响

Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems Pub Date : 2017-11-07 DOI: 10.1145/3139958.3140024

O. Andersen, K. Torp

{"title":"Sampling Frequency Effects on Trajectory Routes and Road Network Travel Time","authors":"O. Andersen, K. Torp","doi":"10.1145/3139958.3140024","DOIUrl":"https://doi.org/10.1145/3139958.3140024","url":null,"abstract":"GPS data is often used for computing travel time in road networks. In addition, GPS data is often map matched to find the routes driven by vehicles. Today GPS data is collected with different sampling periods, however, both the computed travel times and the routes found by map matching algorithms actual depends on the sampling period. This paper proposes a generic approach to study how travel time and map matched routes vary with the sampling period. Two types of map matching algorithms are used, point based where each position is handled individually, and trajectory based where positions from a vehicle is consider a data stream. A baseline is created using a real-world data set of 455 million positions from 368 vehicles collected with a sampling period of 1 second. This data set is downsampled to 8 data sets with sampling periods between 2 and 120 seconds. This downsampling enables an apple-to-apple comparison of travel time computation and route restoration for different sampling periods. The main conclusion is that travel times are reasonably accurate if the sampling period is 5 second or below for the point-based method and 20 seconds or below for the trajectory-based method. GPS data collected with 60 second is to inaccurate to be used for computing travel times. Trajectory-based map matching works best if the sampling period is 20 seconds or below.","PeriodicalId":270649,"journal":{"name":"Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124782811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Improved Road Network Reconstruction using Discrete Morse Theory 基于离散莫尔斯理论的改进路网重建

Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems Pub Date : 2017-11-07 DOI: 10.1145/3139958.3140031

T. Dey, Jiayuan Wang, Yusu Wang

引用次数: 21

Towards Ubiquitous Accessibility Digital Maps for Smart Cities 面向无处不在的智能城市数字地图

Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems Pub Date : 2017-11-07 DOI: 10.1145/3139958.3139978

Heba Aly, M. Youssef, A. Agrawala

{"title":"Towards Ubiquitous Accessibility Digital Maps for Smart Cities","authors":"Heba Aly, M. Youssef, A. Agrawala","doi":"10.1145/3139958.3139978","DOIUrl":"https://doi.org/10.1145/3139958.3139978","url":null,"abstract":"Designing indoor and outdoor spaces to become accessible for people with disabilities is of paramount importance. Accessibility leads to improvements in human rights and business outcomes; due to inclusion of a broader range of the population. For example, adding braille writing to signs and installing ramps allow visually-impaired people and the wheel-chaired to navigate on their own. While digital-maps have evolved in recent years to become a part of our everyday life, available ones primarily cover vehicular roads only with limited, if any, accessibility information. This highly limits the range of applications they can support. In this paper, we present our vision for ubiquitous accessibility digital-maps for smart cities; where the maps' indoor and outdoor spaces are automatically updated with the various accessibility-features and marked to assess their accessibility levels for the different disability types such as vision-impairment, wheel-chaired, deafness, etc. To realize this vision, we describe an architecture for a crowd-sourcing-based system to automatically construct the accessibility maps. In addition, we discuss the multi-disciplinary challenges that have to be addressed to materialize it as well as the current pioneering efforts in the research community related to our vision.","PeriodicalId":270649,"journal":{"name":"Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125793802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 11

ST-COPOT: Spatio-temporal Clustering with Contour Polygon Trees ST-COPOT:基于轮廓多边形树的时空聚类

Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems Pub Date : 2017-11-07 DOI: 10.1145/3139958.3140051

Yongli Zhang, C. Eick

{"title":"ST-COPOT: Spatio-temporal Clustering with Contour Polygon Trees","authors":"Yongli Zhang, C. Eick","doi":"10.1145/3139958.3140051","DOIUrl":"https://doi.org/10.1145/3139958.3140051","url":null,"abstract":"Nowadays, growing effort has been put to develop spatio-temporal clustering approaches that are capable of discovering interesting patterns in large spatio-temporal data streams. In this paper, we propose a 3-phase serial, density-contour based clustering algorithm called ST-COPOT, which can identify spatio-temporal cluster at multiple levels of density granularity. ST-COPOT takes the point cloud data as input and divides it into batches, next, it employs a non-parametric kernel density estimation approach and contouring algorithms to obtain spatial clusters; at last, spatio-temporal clusters are formed by identifying continuing relationships between spatial clusters in consecutive batches. Moreover, a novel data structure called contour polygon tree is introduced as a compact representation of the spatial clusters obtained for each batch for different density thresholds, and a family of novel distance functions that operate on contour polygon trees are proposed to identify continuing clusters. The experimental results on NYC taxi trips data show that ST-COPOT can effectively discover interesting spatio-temporal patterns in taxi pickup location streams.","PeriodicalId":270649,"journal":{"name":"Proceedings of the 25th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130239487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4