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SinoGrids: a practice for open urban data in China / Xinyue Ye in Cartography and Geographic Information Science, vol 43 n° 5 (November 2016)  

Public [article]  inCartography and Geographic Information Science > vol 43 n° 5 (November 2016) . - pp 379 - 392 Titre : SinoGrids: a practice for open urban data in China Type de document : Article/Communication Auteurs : Xinyue Ye, Auteur ; Qunying Huang, Auteur ; Wenwen Li, Auteur Année de publication : 2016 Article en page(s) : pp 379 - 392 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes descripteurs IGN] base de données urbaines [Termes descripteurs IGN] Chine [Termes descripteurs IGN] données localisées des bénévoles [Termes descripteurs IGN] données massives [Termes descripteurs IGN] données ouvertes [Termes descripteurs IGN] interface utilisateur [Termes descripteurs IGN] partage de données localisées [Termes descripteurs IGN] planification urbaine [Termes descripteurs IGN] ville intelligente Résumé : (Auteur) In the past decade, an explosion of data has taken place in Chinese cities due to widespread use of mobile Internet devices, Web 2.0 applications, and the development of the “Wired City.” With advances in data storage and high-performance computing, big/open urban data have opened up important avenues for urban studies, planning practice, and commercial consultancy. Urban researchers and planners are eager to make use of these abundant, sophisticated, and dynamic data to deepen their understanding on urban form and functions. However, in practice, access to such urban data is limited in China due to institutional constraints on data distribution and data holders’ hesitation to share data. And this hampers urban analytics. To draw reliable conclusions about the workings of complex urban systems, efficient and effective interoperation of multisource urban datasets is needed. Also, dealing with the heterogeneity between datasets is an equally critical challenge, especially for urban planners and government officers. They would derive value from data analytics, but have little data processing experience. To address these issues, we initiated SinoGrids (Plan Xu Xiake), a crowdsourcing platform that standardizes (or “downscales”) microscale urban data in China to facilitate its sharing and interoperation. To assess the performance evaluation of SinoGrids, we propose field-testing with actual urban data and their potential users. Digital desert, a son project of SinoGrids is also included. Numéro de notice : A2016-689 Thématique : GEOMATIQUE Nature : Article DOI : https://doi.org/10.1080/15230406.2015.1129914 En ligne : https://doi.org/10.1080/15230406.2015.1129914 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82017 [article]

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Crowdsourcing functions of the living city from Twitter and Foursquare data / Xiaolu Zhou in Cartography and Geographic Information Science, vol 43 n° 5 (November 2016)  

Public [article]  inCartography and Geographic Information Science > vol 43 n° 5 (November 2016) . - pp 393 - 404 Titre : Crowdsourcing functions of the living city from Twitter and Foursquare data Type de document : Article/Communication Auteurs : Xiaolu Zhou, Auteur ; Liang Zhang, Auteur Année de publication : 2016 Article en page(s) : pp 393 - 404 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes descripteurs IGN] analyse spatio-temporelle [Termes descripteurs IGN] Boston (Massachusetts) [Termes descripteurs IGN] Chicago (Illinois) [Termes descripteurs IGN] dimension temporelle [Termes descripteurs IGN] données issues des réseaux sociaux [Termes descripteurs IGN] données localisées des bénévoles [Termes descripteurs IGN] géoétiquetage [Termes descripteurs IGN] planification urbaine [Termes descripteurs IGN] réseau social [Termes descripteurs IGN] système d'information géographique [Termes descripteurs IGN] ville Résumé : (Auteur) Urban functions are closely related to people’s spatiotemporal activity patterns, transportation needs, and a city’s business distribution and development trends. Studies investigating urban functions have used different data sources, such as remotely sensed imageries, observation, photography, and cognitive maps. However, these data sources usually suffer from low spatial, temporal, and thematic resolution. This article attempts to investigate human activities to understand urban functions through crowdsourcing social media data. In this study, we mined Twitter and Foursquare data to extract and analyze six types of human activities. The spatiotemporal analysis revealed hotspots for different activity intensities at different temporal resolution. We also applied the classified model in a real-time system to extract information of various urban functions. This study demonstrates the significance and usefulness of social sensing in analyzing urban functions. By combining different platforms of social media data and analyzing people’s geo-tagged city experience, this article contributes to leverage voluntary local knowledge to better depict human dynamics, discover spatiotemporal city characteristics, and convey information about cities. Numéro de notice : A2016-690 Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/15230406.2015.1128852 En ligne : https://doi.org/10.1080/15230406.2015.1128852 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82018 [article]

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How many samples are needed? An investigation of binary logistic regression for selective omission in a road network / Qi Zhou in Cartography and Geographic Information Science, vol 43 n° 5 (November 2016)  

Public [article]  inCartography and Geographic Information Science > vol 43 n° 5 (November 2016) . - pp 405 - 416 Titre : How many samples are needed? An investigation of binary logistic regression for selective omission in a road network Type de document : Article/Communication Auteurs : Qi Zhou, Auteur ; Zhilin Li, Auteur Année de publication : 2016 Article en page(s) : pp 405 - 416 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] apprentissage dirigé [Termes descripteurs IGN] échantillonnage [Termes descripteurs IGN] généralisation cartographique automatisée [Termes descripteurs IGN] régression logistique [Termes descripteurs IGN] réseau routier [Vedettes matières IGN] Généralisation Résumé : (Auteur) Selective omission in a road network (or road selection) means to retain more important roads, and it is a necessary operator to transform a road network at a large scale to that at a smaller scale. This study discusses the use of the supervised learning approach to road selection, and investigates how many samples are needed for a good performance of road selection. More precisely, the binary logistic regression is employed and three road network data with different sizes and different target scales are involved for testing. The different percentages and numbers of strokes are randomly chosen for training a logistic regression model, which is further applied into the untrained strokes for validation. The performances of using the different sample sizes are mainly evaluated by an error rate estimate. Significance tests are also employed to investigate whether the use of different sample sizes shows statistically significant differences. The experimental results show that in most cases, the error rate estimate is around 0.1–0.2; more importantly, only a small number (e.g., 50–100) of training samples is needed, which indicates the usability of binary logistic regression for road selection. Numéro de notice : A2016-691 Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/15230406.2015.1104265 En ligne : https://doi.org/10.1080/15230406.2015.1104265 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82019 [article]

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Travel time estimation at intersections based on low-frequency spatial-temporal GPS trajectory big data / Lulian Tang in Cartography and Geographic Information Science, vol 43 n° 5 (November 2016)  

Public [article]  inCartography and Geographic Information Science > vol 43 n° 5 (November 2016) . - pp 417 - 426 Titre : Travel time estimation at intersections based on low-frequency spatial-temporal GPS trajectory big data Type de document : Article/Communication Auteurs : Lulian Tang, Auteur ; Zihan Kan, Auteur ; Xia Zhang, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 417 - 426 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes descripteurs IGN] carrefour [Termes descripteurs IGN] coordonnées GPS [Termes descripteurs IGN] dimension temporelle [Termes descripteurs IGN] données massives [Termes descripteurs IGN] fréquence [Termes descripteurs IGN] itinéraire [Termes descripteurs IGN] logique floue [Termes descripteurs IGN] taxi [Termes descripteurs IGN] temps de trajet [Termes descripteurs IGN] trafic routier [Termes descripteurs IGN] Wuhan (Chine) Résumé : (Auteur) Intersections are the critical parts where different traffic flows converge and change directions, forming “bottlenecks” and “clog points” in urban traffic. Intersection travel time is an important parameter for public route planning, traffic management, and engineering optimization. Based on low-frequency spatial-temporal Global Positioning System (GPS) trace data, this article presents a novel method for estimating intersection travel time. The proposed method first analyzes the different travel patterns of vehicles through an intersection, then determines the range of an intersection dynamically and reasonably, and obtains traffic flow speed and delay at the intersection under different travel patterns using a fuzzy fitting approach. Finally, the average intersection travel time is estimated from traffic flow speed and delay and intersection range in different travel patterns. Wuhan road network data and GPS trace data from taxicabs were tested in the experiments and the results show that the proposed method can improve the accuracy of travel time estimation at city intersections. Numéro de notice : A2016-692 Thématique : GEOMATIQUE/POSITIONNEMENT Nature : Article DOI : 10.1080/15230406.2015.1130649 En ligne : https://doi.org/10.1080/15230406.2015.1130649 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82029 [article]

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The socio-environmental data explorer (SEDE) : a social media–enhanced decision support system to explore risk perception to hazard events / Eric Shook in Cartography and Geographic Information Science, vol 43 n° 5 (November 2016)  

Public [article]  inCartography and Geographic Information Science > vol 43 n° 5 (November 2016) . - pp 427 - 441 Titre : The socio-environmental data explorer (SEDE) : a social media–enhanced decision support system to explore risk perception to hazard events Type de document : Article/Communication Auteurs : Eric Shook, Auteur ; Victoria K. Turner, Auteur Année de publication : 2016 Article en page(s) : pp 427 - 441 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes descripteurs IGN] analyse de données [Termes descripteurs IGN] données environnementales [Termes descripteurs IGN] Etats-Unis [Termes descripteurs IGN] exploration de données [Termes descripteurs IGN] neige [Termes descripteurs IGN] outil d'aide à la décision [Termes descripteurs IGN] perception [Termes descripteurs IGN] réseau social [Termes descripteurs IGN] risque environnemental [Termes descripteurs IGN] risque technologique [Termes descripteurs IGN] tempête [Termes descripteurs IGN] temps réel Résumé : (Auteur) Social media are increasingly recognized as a useful data source for understanding social response to hazard events in real time and in post-event analysis. This article establishes social media–enhanced decision support systems (SME-DSS) as a synergistic integration of social media and decision support systems (DSSs) to provide structured access to native, near real-time data from a large and diverse population to assess social response to social, environmental, and technological risk and hazard events. We introduce a prototype SME-DSS entitled socio-environmental data explorer (SEDE) to explore the opportunities and challenges of leveraging social media for decision support. We use a winter storm during 25–28 January 2015 that accumulated record amounts of snow along the East Coast of the United States as a case study to evaluate SEDE in helping assess social response to environmental risk and hazard events as well as evaluate social media as a theoretical component within the social amplification of risk framework (SARF) that serves as a theoretical foundation for SME-DSS. Numéro de notice : A2016-693 Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/15230406.2015.1131627 En ligne : https://doi.org/10.1080/15230406.2015.1131627 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82030 [article]

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Characterizing European urban settlements from population data : a cartographic approach / David Serano Giné in Cartography and Geographic Information Science, vol 43 n° 5 (November 2016)  

Public [article]  inCartography and Geographic Information Science > vol 43 n° 5 (November 2016) . - pp 442 - 453 Titre : Characterizing European urban settlements from population data : a cartographic approach Type de document : Article/Communication Auteurs : David Serano Giné, Auteur ; A. Russo, Auteur Année de publication : 2016 Article en page(s) : pp 442 - 453 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes descripteurs IGN] caractérisation [Termes descripteurs IGN] densité de population [Termes descripteurs IGN] données démographiques [Termes descripteurs IGN] données vectorielles [Termes descripteurs IGN] milieu urbain [Termes descripteurs IGN] Union Européenne [Termes descripteurs IGN] ville Résumé : (Auteur) The cartographic identification and characterization of urban settlements is problematic, particularly in varied areas or in large geographical extensions. This is due to the divergence between morphological area structures and data attribution, which is generally available at the level of administrative units. Most existing experiences focus on small regions or use indirect data, from which only indirect information can be derived. This paper proposes an identification of urban settlements in the European Union space, which combines urban population and shape through geographic information system (GIS) techniques. For that purpose, 1 km2 cells with associated population data are used. A procedure is developed establishing three different types of urban settlements, according to population and population density values: high-density urban clusters, small and medium-sized towns, and very small towns. A validation of this procedure is performed using direct survey from local experts in 10 selected study areas. The final results show that 78,307 urban settlements can be identified: 88.17% of them are classified as “very small towns,” 10.75% as “small and medium-sized towns,” and 1.08% as high-density urban clusters. This exercise generates new information for the European Union and surrounding countries, and yields the basis for further research. All GIS operations are performed using vector layers, which is not usual in large-area regional studies. Numéro de notice : A2016-694 Thématique : GEOMATIQUE Nature : Article DOI : https://doi.org/10.1080/15230406.2015.1076737 En ligne : https://doi.org/10.1080/15230406.2015.1076737 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82032 [article]

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Fourier-based multi-scale representation and progressive transmission of cartographic curves on the internet / Pengcheng Liu in Cartography and Geographic Information Science, vol 43 n° 5 (November 2016)  

Public [article]  inCartography and Geographic Information Science > vol 43 n° 5 (November 2016) . - pp 454 - 468 Titre : Fourier-based multi-scale representation and progressive transmission of cartographic curves on the internet Type de document : Article/Communication Auteurs : Pengcheng Liu, Auteur ; Xingong Li, Auteur ; Weibo Liu, Auteur ; Tinghua Ai, Auteur Année de publication : 2016 Article en page(s) : pp 454 - 468 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] carte topographique [Termes descripteurs IGN] contour [Termes descripteurs IGN] généralisation cartographique automatisée [Termes descripteurs IGN] géomatique web [Termes descripteurs IGN] ligne (géométrie) [Termes descripteurs IGN] représentation multiple [Termes descripteurs IGN] série de Fourier [Termes descripteurs IGN] transmission de données [Vedettes matières IGN] Généralisation Résumé : (Auteur) Automatic generation of multi-scale representations from the same spatial data source has been the research focus in map generalization for a long time. Based on the Fourier technique, this paper proposes a continuous, multi-scale representation model for progressive transformation of cartographic curves on the Internet. In our method, all the curves, whether closed or open, are depicted as periodical functions which are further expressed as Fourier series. The convergence degrees of the Fourier series are explored for different kinds of curves, and truncating frequencies are derived based on the similarity between the original and reconstructed curves. Using information theory and the Radical Law in cartography, the relationship between map scales and Fourier frequencies is established. Based on the proposed multi-scale model, we also introduce the principles and implementation of a progressive transmission method. Our method is evaluated using the contours from a topographic map. The results show that our model is a valid approach to multi-scale representation of cartographic curves. Numéro de notice : A2016-695 Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/15230406.2015.1088799 En ligne : https://doi.org/10.1080/15230406.2015.1088799 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82034 [article]

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