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Advancing science with VGI: Reproducibility and replicability of recent studies / Franck O. Ostermann in Transactions in GIS, vol 21 n° 2 (April 2017)  

Public [article]  inTransactions in GIS > vol 21 n° 2 (April 2017) . - pp 224 – 237 Titre : Advancing science with VGI: Reproducibility and replicability of recent studies Type de document : Article/Communication Auteurs : Franck O. Ostermann, Auteur ; Carlos Granell, Auteur Année de publication : 2017 Article en page(s) : pp 224 – 237 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] diffusion de données [Termes IGN] données localisées des bénévoles [Termes IGN] gestion de crise [Termes IGN] réplication [Termes IGN] source de données [Termes IGN] test de performance Résumé : (auteur) In scientific research, reproducibility and replicability are requirements to ensure the advancement of our body of knowledge. This holds true also for VGI-related research and studies. However, the characteristics of VGI suggest particular difficulties in ensuring reproducibility and replicability. In this article, we aim to examine the current situation in VGI-related research, and identify strategies to ensure realization of its full potential. To do so, we first investigate the different aspects of reproducibility and replicability and their impact on VGI-related research. These impacts are different depending on the objectives of the study. Therefore, we examine the study focus of VGI-related research to assess the current body of research and structure our assessment. This work is based on a rigorous review of the elements of reproducibility and a systematic mapping and analysis of 58 papers on the use of VGI in the crisis management field. Results of our investigation show that reproducibility issues related to data are a serious concern, while reproducibility issues related to analysis methods and processes face fewer challenges. However, since most studies still focus on analyzing the source data, reproducibility and replicability are still an unsolved problem in VGI-related research. Therefore, we show initiatives tackling the problem, and finally formulate strategies to improve the situation. Numéro de notice : A2017-164 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12195 En ligne : http://dx.doi.org/10.1111/tgis.12195 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84698 [article]

VGDI – advancing the concept: Volunteered geo-dynamic information and its benefits for population dynamics modeling / Christoph Aubrecht in Transactions in GIS, vol 21 n° 2 (April 2017)  

Public [article]  inTransactions in GIS > vol 21 n° 2 (April 2017) Titre : VGDI – advancing the concept: Volunteered geo-dynamic information and its benefits for population dynamics modeling Type de document : Article/Communication Auteurs : Christoph Aubrecht, Auteur ; Dilek Özceylan Aubrecht, Auteur ; Joachim Ungar, Auteur ; et al., Auteur Année de publication : 2017 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] connaissance thématique [Termes IGN] dimension temporelle [Termes IGN] données localisées des bénévoles [Termes IGN] extraction de données [Termes IGN] géomatique [Termes IGN] modèle dynamique Résumé : (auteur) The concept of Volunteered Geographic Information (VGI) has progressed from being an exotic prospect to making a profound impact on GIScience and geography in general, as initially anticipated. However, while massive and manifold data is continuously produced voluntarily and applications are built for information and knowledge extraction, the initially introduced concept of VGI lacks certain methodological perspectives in this regard which have not been fully elaborated. In this article we highlight and discuss an important gap in this concept, i.e. the lack of formal acknowledgment of temporal aspects. By coining the proposed advanced framework ‘Volunteered Geo-Dynamic Information’ (VGDI), we attempt to lay the ground for full conceptual and applied spatio-temporal integration. To illustrate that integrative approach of VGDI and its benefits, we describe the potential impact on the field of dynamic population distribution modeling. While traditional approaches in that domain rely on survey-based data and statistics as well as static geographic information, the use of VGDI enables a dynamic setup. Foursquare venue and user check-in data are presented for a test site in Lisbon, Portugal. Two core modules of spatio-temporal population assessment are thereby addressed, namely time use profiling and target zone characterization, motivated by the potential integration in existing population dynamics frameworks such as the DynaPop model. Numéro de notice : A2017-165 Affiliation des auteurs : non IGN Thématique : SOCIETE NUMERIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12203 En ligne : http://dx.doi.org/DOI: 10.1111/tgis.12203 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84699 [article]

Improving large area population mapping using geotweet densities / Nirav N. Patel in Transactions in GIS, vol 21 n° 2 (April 2017)  

Public [article]  inTransactions in GIS > vol 21 n° 2 (April 2017) . - pp 317 – 331 Titre : Improving large area population mapping using geotweet densities Type de document : Article/Communication Auteurs : Nirav N. Patel, Auteur ; Forrest R. Stevens, Auteur ; Zhuojie Huang, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 317 – 331 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] cartographie dynamique [Termes IGN] cartographie statistique [Termes IGN] classification par forêts d'arbres décisionnels [Termes IGN] densité de population [Termes IGN] données issues des réseaux sociaux [Termes IGN] Indonésie [Termes IGN] recensement [Termes IGN] répartition géographique [Termes IGN] Twitter [Vedettes matières IGN] Géovisualisation Résumé : (auteur) Many different methods are used to disaggregate census data and predict population densities to construct finer scale, gridded population data sets. These methods often involve a range of high resolution geospatial covariate datasets on aspects such as urban areas, infrastructure, land cover and topography; such covariates, however, are not directly indicative of the presence of people. Here we tested the potential of geo-located tweets from the social media application, Twitter, as a covariate in the production of population maps. The density of geo-located tweets in 1x1 km grid cells over a 2-month period across Indonesia, a country with one of the highest Twitter usage rates in the world, was input as a covariate into a previously published random forests-based census disaggregation method. Comparison of internal measures of accuracy and external assessments between models built with and without the geotweets showed that increases in population mapping accuracy could be obtained using the geotweet densities as a covariate layer. The work highlights the potential for such social media-derived data in improving our understanding of population distributions and offers promise for more dynamic mapping with such data being continually produced and freely available. Numéro de notice : A2017-166 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/SOCIETE NUMERIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12214 En ligne : http://dx.doi.org/10.1111/tgis.12214 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84700 [article]

A spatial anomaly points and regions detection method using multi-constrained graphs and local density / Yan Shi in Transactions in GIS, vol 21 n° 2 (April 2017)  

Public [article]  inTransactions in GIS > vol 21 n° 2 (April 2017) . - pp 376 – 405 Titre : A spatial anomaly points and regions detection method using multi-constrained graphs and local density Type de document : Article/Communication Auteurs : Yan Shi, Auteur ; Min Deng, Auteur ; Xuexi Yang, Auteur ; Qiliang Liu, Auteur Année de publication : 2017 Article en page(s) : pp 376 – 405 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] analyse de données [Termes IGN] analyse spatiale [Termes IGN] attribut sémantique [Termes IGN] cartographie statistique [Termes IGN] détection d'anomalie [Termes IGN] graphe [Termes IGN] interpolation spatiale [Termes IGN] programmation par contraintes [Termes IGN] triangulation de Delaunay Résumé : (auteur) Spatial anomalies may be single points or small regions whose non-spatial attribute values are significantly inconsistent with those of their spatial neighborhoods. In this article, a Spatial Anomaly Points and Regions Detection method using multi-constrained graphs and local density (SAPRD for short) is proposed. The SAPRD algorithm first models spatial proximity relationships between spatial entities by constructing a Delaunay triangulation, the edges of which provide certain statistical characteristics. By considering the difference in non-spatial attributes of adjacent spatial entities, two levels of non-spatial attribute distance constraints are imposed to improve the proximity graph. This produces a series of sub-graphs, and those with very few entities are identified as candidate spatial anomalies. Moreover, the spatial anomaly degree of each entity is calculated based on the local density. A spatial interpolation surface of the spatial anomaly degree is generated using the inverse distance weight, and this is utilized to reveal potential spatial anomalies and reflect their whole areal distribution. Experiments on both simulated and real-life spatial databases demonstrate the effectiveness and practicability of the SAPRD algorithm. Numéro de notice : A2017-167 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12208 En ligne : http://dx.doi.org/10.1111/tgis.12208 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84701 [article]

A method for matching crowd-sourced and authoritative geospatial data / Heshan Du in Transactions in GIS, vol 21 n° 2 (April 2017)  

Public [article]  inTransactions in GIS > vol 21 n° 2 (April 2017) . - pp 406 – 427 Titre : A method for matching crowd-sourced and authoritative geospatial data Type de document : Article/Communication Auteurs : Heshan Du, Auteur ; Natasha Alechina, Auteur ; Michael Jackson, Auteur ; Glen Hart, Auteur Année de publication : 2017 Article en page(s) : pp 406 – 427 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] appariement automatique [Termes IGN] appariement de données localisées [Termes IGN] données ouvertes [Termes IGN] France (administrative) [Termes IGN] géomatique web [Termes IGN] Grande-Bretagne [Termes IGN] infrastructure nationale des données localisées [Termes IGN] OpenStreetMap [Termes IGN] organisme cartographique national Résumé : (auteur) A method for matching crowd-sourced and authoritative geospatial data is presented. A level of tolerance is defined as an input parameter as some difference in the geometry representation of a spatial object is to be expected. The method generates matches between spatial objects using location information and lexical information, such as names and types, and verifies consistency of matches using reasoning in qualitative spatial and description logic. We test the method by matching geospatial data from OpenStreetMap and the national mapping agencies of Great Britain and France. We also analyze how the level of tolerance affects the precision and recall of matching results for the same geographic area using 12 different levels of tolerance within a range of 1 to 80 m. The generated matches show potential in helping enrich and update geospatial data. Numéro de notice : A2017-168 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12210 En ligne : http://dx.doi.org/10.1111/tgis.12210 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84702 [article]