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The effect of intra-urban mobility flows on the spatial heterogeneity of social media activity: investigating the response to rainfall events / Sidgley Camargo de Andrade in International journal of geographical information science IJGIS, vol 36 n° 6 (June 2022)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 36 n° 6 (June 2022) . - pp 1140 - 1165 Titre : The effect of intra-urban mobility flows on the spatial heterogeneity of social media activity: investigating the response to rainfall events Type de document : Article/Communication Auteurs : Sidgley Camargo de Andrade, Auteur ; João Porto de Albuquerque, Auteur ; Camilo Restrepo-Estrada, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 1140 - 1165 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] auto-régression [Termes IGN] distribution spatiale [Termes IGN] données issues des réseaux sociaux [Termes IGN] données socio-économiques [Termes IGN] hétérogénéité spatiale [Termes IGN] mobilité urbaine [Termes IGN] modélisation spatio-temporelle [Termes IGN] pluie [Termes IGN] précipitation [Termes IGN] Sao Paulo [Termes IGN] Twitter Résumé : (auteur) Although it is acknowledged that urban inequalities can lead to biases in the production of social media data, there is a lack of studies which make an assessment of the effects of intra-urban movements in real-world urban analytics applications, based on social media. This study investigates the spatial heterogeneity of social media with regard to the regular intra-urban movements of residents by means of a case study of rainfall-related Twitter activity in São Paulo, Brazil. We apply a spatial autoregressive model that uses population and income as covariates and intra-urban mobility flows as spatial weights to explain the spatial distribution of the social response to rainfall events in Twitter vis-à-vis rainfall radar data. Results show high spatial heterogeneity in the response of social media to rainfall events, which is linked to intra-urban inequalities. Our model performance (R2=0.80) provides evidence that urban mobility flows and socio-economic indicators are significant factors to explain the spatial heterogeneity of thematic spatiotemporal patterns extracted from social media. Therefore, urban analytics research and practice should consider not only the influence of socio-economic profile of neighborhoods but also the spatial interaction introduced by intra-urban mobility flows to account for spatial heterogeneity when using social media data. Numéro de notice : A2022-405 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2021.1957898 Date de publication en ligne : 03/08/2021 En ligne : https://doi.org/10.1080/13658816.2021.1957898 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100717 [article]

An improved rainfall-threshold approach for robust prediction and warning of flood and flash flood hazards / Geraldo Moura Ramos Filho in Natural Hazards, Vol 105 n° 3 (February 2021)  

Public [article]  inNatural Hazards > Vol 105 n° 3 (February 2021) . - pp 2409 - 2429 Titre : An improved rainfall-threshold approach for robust prediction and warning of flood and flash flood hazards Type de document : Article/Communication Auteurs : Geraldo Moura Ramos Filho, Auteur ; Victor Hugo Rabelo Coelho, Auteur ; Emerson da Silva Freitas, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : pp 2409 - 2429 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] crue [Termes IGN] Indice de précipitations antérieures [Termes IGN] indice de risque [Termes IGN] inondation [Termes IGN] méthode robuste [Termes IGN] prévention des risques [Termes IGN] risque naturel [Termes IGN] Sao Paulo [Termes IGN] seuillage [Termes IGN] surveillance hydrologique Résumé : (auteur) This paper presents an improved method of using threshold of peak rainfall intensity for robust flood/flash flood evaluation and warnings in the state of São Paulo, Brazil. The improvements involve the use of two tolerance levels and the delineating of an intermediate threshold by incorporating an exponential curve that relates rainfall intensity and Antecedent Precipitation Index (API). The application of the tolerance levels presents an average increase of 14% in the Probability of Detection (POD) of flood and flash flood occurrences above the upper threshold. Moreover, a considerable exclusion (63%) of non-occurrences of floods and flash floods in between the two thresholds significantly reduce the number of false alarms. The intermediate threshold using the exponential curves also exhibits improvements for almost all time steps of both hydrological hazards, with the best results found for floods correlating 8-h peak intensity and 8 days API, with POD and Positive Predictive Value (PPV) values equal to 81% and 82%, respectively. This study provides strong indications that the new proposed rainfall threshold-based approach can help reduce the uncertainties in predicting the occurrences of floods and flash floods. Numéro de notice : A2020-204 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s11069-020-04405-x Date de publication en ligne : 03/11/2020 En ligne : https://doi.org/10.1007/s11069-020-04405-x Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97167 [article]

Multi‐temporal transport network models for accessibility studies / Diego Bogado Tomasiello in Transactions in GIS, vol 23 n° 2 (April 2019)  

Public [article]  inTransactions in GIS > vol 23 n° 2 (April 2019) . - pp 203 - 223 Titre : Multi‐temporal transport network models for accessibility studies Type de document : Article/Communication Auteurs : Diego Bogado Tomasiello, Auteur ; Mariana Giannotti, Auteur ; Renato Arbex, Auteur ; Clodoveu Davis, Auteur Année de publication : 2019 Article en page(s) : pp 203 - 223 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] accessibilité [Termes IGN] granularité (informatique) [Termes IGN] modèle conceptuel de données spatio-temporelles [Termes IGN] modélisation spatio-temporelle [Termes IGN] réseau de transport [Termes IGN] Sao Paulo [Termes IGN] urbanisme Résumé : (Auteur) Vehicle tracking is a spatio‐temporal source of high‐granularity travel time information that can be used for transportation planning. However, it is still a challenge to combine data from heterogeneous sources into a dynamic transport network, while allowing for network modifications over time. This article uses conceptual modeling to develop multi‐temporal transport networks in geographic information systems (GIS) for accessibility studies. The proposed multi‐temporal network enables accessibility studies with different temporal granularities and from any location inside the city, resulting in a flexible tool for transport and urban planning. The implemented network is tested in two case studies that focus on socially excluded people in a large global city, São Paulo, Brazil, including accessibility analyses from slum areas. It explores variations within a day and differences between transport modes across time. Case study results indicate how the accessibility is heterogeneous in low‐income regions. Numéro de notice : A2019-249 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12513 Date de publication en ligne : 10/03/2019 En ligne : https://doi.org/10.1111/tgis.12513 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93005 [article]

A high resolution orthomosaic in Brazil / N. Parada in Geoinformatics, vol 12 n° 5 (01/07/2009)

Public [article]  inGeoinformatics > vol 12 n° 5 (01/07/2009) . - pp 22 - 26 Titre : A high resolution orthomosaic in Brazil Type de document : Article/Communication Auteurs : N. Parada, Auteur ; U.W. Palme, Auteur ; et al., Auteur Année de publication : 2009 Article en page(s) : pp 22 - 26 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Orthophotographie, orthoimage [Termes IGN] image à très haute résolution [Termes IGN] image Ikonos [Termes IGN] modèle numérique de terrain [Termes IGN] orthophotoplan numérique [Termes IGN] réseau géodésique [Termes IGN] Sao Paulo Résumé : (Auteur) A high orthomosaic was generated for the 800 km area of the country of Campinas, Brazil, derived from Ikonos satellite imagery, a Digital Terrain model (DTM) generated from WorldView-1 satellite imagery, and an implemented geodetic network of 19 points. The final orthomosaic was generated both in normal color and in false color infrared in order to broaden the possible applications to environmental issues. This result represents a very interesting solution to cover large areas in short time and with a lower cost than traditional aerophotogrammetric methods, thus with basically the same quality, allowing for a better assertive planning and sustainable development of the territory. Copyright GEOinformatics Numéro de notice : A2009-280 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29910 [article]

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Using neural networks and cellular automata for modelling intra-urban land-use dynamics / C.M. Almeida in International journal of geographical information science IJGIS, vol 22 n° 8-9 (august 2008)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 22 n° 8-9 (august 2008) . - pp 943 - 963 Titre : Using neural networks and cellular automata for modelling intra-urban land-use dynamics Type de document : Article/Communication Auteurs : C.M. Almeida, Auteur ; J.M. Gleriani, Auteur ; E.F. Castejon, Auteur ; B.S. Soares-Filho, Auteur Année de publication : 2008 Article en page(s) : pp 943 - 963 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse diachronique [Termes IGN] automate cellulaire [Termes IGN] milieu urbain [Termes IGN] modèle de simulation [Termes IGN] planification urbaine [Termes IGN] réseau neuronal artificiel [Termes IGN] Sao Paulo [Termes IGN] utilisation du sol [Termes IGN] ville Résumé : (Auteur) Empirical models designed to simulate and predict urban land-use change in real situations are generally based on the utilization of statistical techniques to compute the land-use change probabilities. In contrast to these methods, artificial neural networks arise as an alternative to assess such probabilities by means of non-parametric approaches. This work introduces a simulation experiment on intra-urban land-use change in which a supervised back-propagation neural network has been employed in the parameterization of several biophysical and infrastructure variables considered in the simulation model. The spatial land-use transition probabilities estimated thereof feed a cellular automaton (CA) simulation model, based on stochastic transition rules. The model has been tested in a medium-sized town in the Midwest of Sao Paulo State, Piracicaba. A series of simulation outputs for the case study town in the period 1985-1999 were generated, and statistical validation tests were then conducted for the best results, based on fuzzy similarity measures. Copyright Taylor & Francis Numéro de notice : A2008-310 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810701731168 En ligne : https://doi.org/10.1080/13658810701731168 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29303 [article]

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GIS and remote sensing as tools for the simulation of urban land-use change / C.M. Almeida in International Journal of Remote Sensing IJRS, vol 26 n° 4 (February 2005)  

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First direct geodetic link between Europe, Africa and south-America with a multi station VLBI array / Gérard Petit in Bulletin géodésique, vol 63 n° 4 (décembre 1989)

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Positionnement par radio-interférométrie de Atibaia et Nançay dans un système de référence terrestre / Gérard Petit (29/01/1986)

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Nouvelle géographie universelle : la Terre et les hommes, 2. Tome 19 Amérique du sud (2ème partie) / E. Reclus (1894)

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