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Opportunities and impediments for open GIS / Daniel Sui in Transactions in GIS, vol 18 n° 1 (February 2014)  

Public [article]  inTransactions in GIS > vol 18 n° 1 (February 2014) . - pp 1 - 24 Titre : Opportunities and impediments for open GIS Type de document : Article/Communication Auteurs : Daniel Sui, Auteur Année de publication : 2014 Article en page(s) : pp 1 - 24 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] aide à la décision [Termes IGN] données massives [Termes IGN] données ouvertes [Termes IGN] formation [Termes IGN] logiciel libre [Termes IGN] recherche [Termes IGN] SIG ouvert Résumé : (Auteur) The field of GIS (S for Systems, Sciences, Services, and Studies) is at a cross-road in the early 2010s. Aiming to link the multiple visions for the next phase of GIS development, this article suggests that the emerging open GIS should serve as a guiding concept. Contextualized in the broader literature of open science, this article proposes open GIS should include eight dimensions related to data, software, hardware, standards, research, publication, funding, and education. For the GIS community, open GIS offers four exciting opportunities: (1) technology-driven opportunities for addressing challenges posed by the (spatial) big data deluge; (2) application-led opportunities for confronting the problems of a rapidly changing planet; (3) curiosity-inspired, crowd-powered opportunities for the development of an open and geographic citizen science; and (4) education-focused opportunities for implementing the vision of a spatial university. Although there are academic, legal, social/political, and environmental impediments for the practice of open GIS, open GIS will become increasingly important in shaping our research and educational agendas in the future. Numéro de notice : A2014-063 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/SOCIETE NUMERIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12075 Date de publication en ligne : 09/01/2014 En ligne : https://doi.org/10.1111/tgis.12075 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32968 [article]

The co-evolution of residential segregation and the built environment at the turn of the 20th century: A Schelling model / Seth Spielman in Transactions in GIS, vol 18 n° 1 (February 2014)  

Public [article]  inTransactions in GIS > vol 18 n° 1 (February 2014) . - pp 25 - 45 Titre : The co-evolution of residential segregation and the built environment at the turn of the 20th century: A Schelling model Type de document : Article/Communication Auteurs : Seth Spielman, Auteur ; Patrick Harrison, Auteur Année de publication : 2014 Article en page(s) : pp 25 - 45 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes IGN] changement d'occupation du sol [Termes IGN] environnement [Termes IGN] Etats-Unis [Termes IGN] habitat urbain [Termes IGN] histoire [Termes IGN] modélisation [Termes IGN] New Jersey (Etats-Unis) [Termes IGN] population urbaine [Termes IGN] répartition géographique [Termes IGN] système d'information géographique [Termes IGN] ville Résumé : (Auteur) To what degree does the built environment of cities shape the social environment? In this article we use a Schelling-like agent-based model to consider how changes to the built environment of cities relate to changes in residential segregation by income and ethnicity. To develop this model we exploit insights from a high resolution historical GIS which maps 100% of the population of Newark, NJ in 1880. Newark in 1880 had a complex social landscape characterized by areas of significant social and economic segregation and areas of relative integration. We develop a Schelling model capable of reproducing these residential patterns. We use this model to explore the decentralization of housing, a specific phenomenon associated with the demise of the walking city in the late 19th century. Holding agent preferences constant, but allowing the landscape of the Schelling model to evolve in ways that reflect historical changes to the built environment, produces changes to the social landscape that are also consistent with history. Our work suggests that changes in residential segregation do not necessarily imply changes to individual attitudes and preferences. Changes in residential segregation can be generated by changes to the built environment, specifically the geographic distribution of housing. Numéro de notice : A2014-064 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12014 Date de publication en ligne : 05/02/2013 En ligne : https://doi.org/10.1111/tgis.12014 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32969 [article]

CONSTAnT – A conceptual data model for semantic Trajectories of moving objects / Vania Bogorny in Transactions in GIS, vol 18 n° 1 (February 2014)  

Public [article]  inTransactions in GIS > vol 18 n° 1 (February 2014) . - pp 66 - 88 Titre : CONSTAnT – A conceptual data model for semantic Trajectories of moving objects Type de document : Article/Communication Auteurs : Vania Bogorny, Auteur ; Chiara Renso, Auteur ; Artur Ribeiro De Aquino, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 66 - 88 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] information sémantique [Termes IGN] itinéraire [Termes IGN] modèle conceptuel de données [Termes IGN] modèle sémantique de données [Termes IGN] objet mobile Résumé : (Auteur) Several works have been proposed in the last few years for raw trajectory data analysis, and some attempts have been made to define trajectories from a more semantic point of view. Semantic trajectory data analysis has received significant attention recently, but the formal definition of semantic trajectory, the set of aspects that should be considered to semantically enrich trajectories and a conceptual data model integrating these aspects from a broad sense is still missing. This article presents a semantic trajectory conceptual data model named CONSTAnT, which defines the most important aspects of semantic trajectories. We believe that this model will be the foundation for the design of semantic trajectory databases, where several aspects that make a trajectory “semantic” are taken into account. The proposed model includes the concepts of semantic subtrajectory, semantic points, geographical places, events, goals, environment and behavior, to create a general concept of semantic trajectory. The proposed model is the result of several years of work by the authors in an effort to add more semantics to raw trajectory data for real applications. Two application examples and different queries show the flexibility of the model for different domains. Numéro de notice : A2014-065 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12011 Date de publication en ligne : 05/02/2013 En ligne : https://doi.org/10.1111/tgis.12011 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32970 [article]

Analyzing relatedness by toponym co-occurrences on web pages / Yu Liu in Transactions in GIS, vol 18 n° 1 (February 2014)  

Public [article]  inTransactions in GIS > vol 18 n° 1 (February 2014) . - pp 89 - 107 Titre : Analyzing relatedness by toponym co-occurrences on web pages Type de document : Article/Communication Auteurs : Yu Liu, Auteur ; Fahui Wang, Auteur ; Chaogui Kang, Auteur ; et al., Auteur Année de publication : 2014 Article en page(s) : pp 89 - 107 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] analyse spatiale [Termes IGN] Chine [Termes IGN] données massives [Termes IGN] matrice de co-occurrence [Termes IGN] moteur de recherche [Termes IGN] objet géographique [Termes IGN] outil de découverte de connaissances [Termes IGN] relation topologique [Termes IGN] voisinage (relation topologique) Résumé : (Auteur) This research proposes a method for capturing “relatedness between geographical entities” based on the co-occurrences of their names on web pages. The basic assumption is that a higher count of co-occurrences of two geographical places implies a stronger relatedness between them. The spatial structure of China at the provincial level is explored from the co-occurrences of two provincial units in one document, extracted by a web information retrieval engine. Analysis on the co-occurrences and topological distances between all pairs of provinces indicates that: (1) spatially close provinces generally have similar co-occurrence patterns; (2) the frequency of co-occurrences exhibits a power law distance decay effect with the exponent of 0.2; and (3) the co-occurrence matrix can be used to capture the similarity/linkage between neighboring provinces and fed into a regionalization method to examine the spatial organization of China. The proposed method provides a promising approach to extracting valuable geographical information from massive web pages. Numéro de notice : A2014-066 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12011 Date de publication en ligne : 19/03/2013 En ligne : https://doi.org/10.1111/tgis.12011 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32971 [article]

A triangular form-based multiple flow algorithm to estimate overland flow distribution and accumulation on a digital elevation model / Petter Pilesjö in Transactions in GIS, vol 18 n° 1 (February 2014)  

Public [article]  inTransactions in GIS > vol 18 n° 1 (February 2014) . - pp 108 - 124 Titre : A triangular form-based multiple flow algorithm to estimate overland flow distribution and accumulation on a digital elevation model Type de document : Article/Communication Auteurs : Petter Pilesjö, Auteur ; Abdulghani Hasan, Auteur Année de publication : 2014 Article en page(s) : pp 108 - 124 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] données maillées [Termes IGN] flux [Termes IGN] maillage par triangles [Termes IGN] maille triangulaire [Termes IGN] modèle numérique de surface [Termes IGN] tessellation Résumé : (Auteur) In this study, we present a newly developed method for the estimation of surface flow paths on a digital elevation model (DEM). The objective is to use a form-based algorithm, analyzing flow over single cells by dividing them into eight triangular facets and to estimate the surface flow paths on a raster DEM. For each cell on a gridded DEM, the triangular form-based multiple flow algorithm (TFM) was used to distribute flow to one or more of the eight neighbor cells, which determined the flow paths over the DEM. Because each of the eight facets covering a cell has a constant slope and aspect, the estimations of – for example – flow direction and divergence/convergence are more intuitive and less complicated than many traditional raster-based solutions. Experiments were undertaken by estimating the specific catchment area (SCA) over a number of mathematical surfaces, as well as on a real-world DEM. Comparisons were made between the derived SCA by the TFM algorithm with eight other algorithms reported in the literature. The results show that the TFM algorithm produced the closest outcomes to the theoretical values of the SCA compared with other algorithms, derived more consistent outcomes, and was less influenced by surface shapes. The real-world DEM test shows that the TFM was capable of modeling flow distribution without noticeable ‘artefacts’, and its ability to track flow paths makes it an appropriate platform for dynamic surface flow simulation. Numéro de notice : A2014-067 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12015 Date de publication en ligne : 06/02/2013 En ligne : https://doi.org/10.1111/tgis.12015 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32972 [article]

Combining Geo-SOM and hierarchical clustering to explore geospatial data / Chen-Chieh Feng in Transactions in GIS, vol 18 n° 1 (February 2014)  

Public [article]  inTransactions in GIS > vol 18 n° 1 (February 2014) . - pp 125 - 146 Titre : Combining Geo-SOM and hierarchical clustering to explore geospatial data Type de document : Article/Communication Auteurs : Chen-Chieh Feng, Auteur ; Yi-Chen Wang, Auteur ; Chih-Yuan Chen, Auteur Année de publication : 2014 Article en page(s) : pp 125 - 146 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse combinatoire (maths) [Termes IGN] analyse de groupement [Termes IGN] carte de Kohonen [Termes IGN] données localisées [Termes IGN] exploration de données géographiques [Termes IGN] visualisation Résumé : (Auteur) Geo-SOM is a useful geovisualization technique for revealing patterns in spatial data, but is ineffective in supporting interactive exploration of patterns hidden in different Geo-SOM sizes. Based on the divide and group principle in geovisualization, the article proposes a new methodology that combines Geo-SOM and hierarchical clustering to tackle this problem. Geo-SOM was used to “divide” the dataset into several homogeneous subsets; hierarchical clustering was then used to “group” neighboring homogeneous subsets for pattern exploration in different levels of granularity, thus permitting exploration of patterns at multiple scales. An artificial dataset was used for validating the method's effectiveness. As a case study, the rush hour motorcycle flow data in Taipei City, Taiwan were analyzed. Compared with the best result generated solely by Geo-SOM, the proposed method performed better in capturing the homogeneous zones in the artificial dataset. For the case study, the proposed method discovered six clusters with unique data and spatial patterns at different levels of granularity, while the original Geo-SOM only identified two. Among the four hierarchical clustering methods, Ward's clustering performed the best in pattern discovery. The results demonstrated the effectiveness of the approach in visually and interactively exploring data and spatial patterns in geospatial data. Numéro de notice : A2014-068 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12025 Date de publication en ligne : 16/09/2013 En ligne : https://doi.org/10.1111/tgis.12025 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32973 [article]

Airborne LiDAR and terrestrial laser scanning derived vegetation obstruction factors for visibility models / Jayson Murgoitio in Transactions in GIS, vol 18 n° 1 (February 2014)  

Public [article]  inTransactions in GIS > vol 18 n° 1 (February 2014) . - pp 125 - 146 Titre : Airborne LiDAR and terrestrial laser scanning derived vegetation obstruction factors for visibility models Type de document : Article/Communication Auteurs : Jayson Murgoitio, Auteur ; Rupesh Shrestha, Auteur ; Nancy Glenn, Auteur ; Lucas Spaete, Auteur Année de publication : 2014 Article en page(s) : pp 125 - 146 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] arbre (flore) [Termes IGN] base de données dérivée [Termes IGN] contour [Termes IGN] corrélation [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] écosystème forestier [Termes IGN] intégration de données [Termes IGN] Pinus contorta [Termes IGN] régression [Termes IGN] télémétrie laser aéroporté [Termes IGN] télémétrie laser terrestre [Termes IGN] visibilité Résumé : (Auteur) Research presented here explores the feasibility of leveraging vegetation data derived from airborne light detection and ranging (LiDAR) and terrestrial laser scanning (TLS) for visibility modeling. Using LiDAR and TLS datasets of a lodgepole pine (Pinus contorta) dominant ecosystem, tree canopy and trunk obstructions were isolated relevant to a discrete visibility beam in a short-range line-of-sight model. Cumulative obstruction factors from vegetation were compared with reference visibility values from digital photographs along sightline paths. LiDAR-derived tree factors were augmented with single-scan TLS data for obstruction prediction. Good correlation between datasets was found up to 10 m from the terrestrial scanner, but fine scale visibility modeling was problematic at longer distances. Analysis of correlation and regression results reveal the influence of obstruction shadowing inherent to discrete LiDAR and TLS, potentially limiting the feasibility of modeling visibility over large areas with similar technology. However, the results support the potential for TLS-derived subcanopy metrics for augmenting large amounts of aerial LiDAR data to significantly improve models of forest structure. Subtle LiDAR processing improvements, including more accurate tree delineation through higher point density aerial data, combined with better vegetation quantification processes for TLS data, will advance the feasibility and accuracy of data integration. Numéro de notice : A2014-069 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12022 Date de publication en ligne : 17/05/2013 En ligne : https://doi.org/10.1111/tgis.12022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32974 [article]