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Drought-vulnerable vegetation increases exposure of disadvantaged populations to heatwaves under global warming: A case study from Los Angeles / Chunyu Dong in Sustainable Cities and Society, vol 93 (June 2023)  

Public [article]  inSustainable Cities and Society > vol 93 (June 2023) . - n° 104488 Titre : Drought-vulnerable vegetation increases exposure of disadvantaged populations to heatwaves under global warming: A case study from Los Angeles Type de document : Article/Communication Auteurs : Chunyu Dong, Auteur ; Yu Yan, Auteur ; Jie Guo, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : n° 104488 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] changement climatique [Termes IGN] climat urbain [Termes IGN] données socio-économiques [Termes IGN] espace vert [Termes IGN] ilot thermique urbain [Termes IGN] image Terra-MODIS [Termes IGN] Los Angeles [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] sécheresse [Termes IGN] température au sol Résumé : (auteur) Urban vegetation is valuable in alleviating local heatwaves. However, drought may decrease vegetation health and limit this cooling effect. Here we use satellite-based Normalized Difference Vegetation Index (NDVI) and Palmer Drought Severity Index (PDSI) to investigate the sensitivity of urban vegetation to drought in Coastal Greater Los Angeles (CGLA) from 2001 to 2020. We applied four statistical models to analyze the relations between 15 socioeconomic variables and the vegetation's sensitivity to drought. We then examined the changes in the cooling effect of the urban vegetation during drought and non-drought periods using remotely sensed land surface temperature (LST) data. The results suggest that economically disadvantaged areas with higher proportions of Hispanics and Blacks are typified by vegetation more sensitive to drought, which is likely linked to inequality in water use. Moreover, these populations experience a lower degree of vegetation cooling effects and higher exposure to heatwaves. The findings of this study imply that the potential of a community's vegetation in mitigating heatwaves is significantly influenced by the socioeconomic conditions of the community. Increasing the resilience of urban vegetation to drought in disadvantaged communities may help promote environmentally sustainable and socially resilient cities under a warming climate. Numéro de notice : A2023-191 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1016/j.scs.2023.104488 Date de publication en ligne : 26/02/2023 En ligne : https://doi.org/10.1016/j.scs.2023.104488 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102972 [article]

Los Angeles as a digital place: The geographies of user‐generated content / Andrea Ballatore in Transactions in GIS, Vol 24 n° 4 (August 2020)  

Public [article]  inTransactions in GIS > Vol 24 n° 4 (August 2020) . - 23 p. Titre : Los Angeles as a digital place: The geographies of user‐generated content Type de document : Article/Communication Auteurs : Andrea Ballatore, Auteur ; Stefano de Sabbata, Auteur Année de publication : 2020 Article en page(s) : 23 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] analyse spatiale [Termes IGN] centre urbain [Termes IGN] contenu généré par les utilisateurs [Termes IGN] distribution spatiale [Termes IGN] données multisources [Termes IGN] données socio-économiques [Termes IGN] exploration de données géographiques [Termes IGN] Foursquare [Termes IGN] Los Angeles [Termes IGN] modèle de régression [Termes IGN] OpenStreetMap [Termes IGN] participation du public [Termes IGN] représentation géographique [Termes IGN] réseau social [Termes IGN] réseau social géodépendant [Termes IGN] Twitter Résumé : (auteur) Online representations of places are becoming pivotal in informing our understanding of urban life. Content production on online platforms is grounded in the geography of their users and their digital infrastructure. These constraints shape place representation, that is, the amount, quality, and type of digital information available in a geographic area. In this article we study the place representation of user‐generated content (UGC) in Los Angeles County, relating the spatial distribution of the data to its geo‐demographic context. Adopting a comparative and multi‐platform approach, this quantitative analysis investigates the spatial relationship between four diverse UGC datasets and their context at the census tract level (about 685,000 geo‐located tweets, 9,700 Wikipedia pages, 4 million OpenStreetMap objects, and 180,000 Foursquare venues). The context includes the ethnicity, age, income, education, and deprivation of residents, as well as public infrastructure. An exploratory spatial analysis and regression‐based models indicate that the four UGC platforms possess distinct geographies of place representation. To a moderate extent, the presence of Twitter, OpenStreetMap, and Foursquare data is influenced by population density, ethnicity, education, and income. However, each platform responds to different socio‐economic factors and clusters emerge in disparate hotspots. Unexpectedly, Twitter data tend to be located in denser, more deprived areas, and the geography of Wikipedia appears peculiar and harder to explain. These trends are compared with previous findings for the area of Greater London. Numéro de notice : A2020-671 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/SOCIETE NUMERIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12600 Date de publication en ligne : 02/01/2020 En ligne : https://doi.org/10.1111/tgis.12600 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96156 [article]

Delineating and modeling activity space using geotagged social media data / Lingqian Hu in Cartography and Geographic Information Science, vol 47 n° 3 (May 2020)  

Public [article]  inCartography and Geographic Information Science > vol 47 n° 3 (May 2020) . - pp 277 - 288 Titre : Delineating and modeling activity space using geotagged social media data Type de document : Article/Communication Auteurs : Lingqian Hu, Auteur ; Zhenhong Li, Auteur ; Xinyue Ye, Auteur Année de publication : 2020 Article en page(s) : pp 277 - 288 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] distance [Termes IGN] données localisées des bénévoles [Termes IGN] données massives [Termes IGN] données socio-économiques [Termes IGN] logement [Termes IGN] loisir [Termes IGN] Los Angeles [Termes IGN] quartier [Termes IGN] réseau social [Termes IGN] sport [Termes IGN] Twitter [Termes IGN] voisinage (relation topologique) [Termes IGN] zone urbaine Résumé : (auteur) It has become increasingly important in spatial equity studies to understand activity spaces – where people conduct regular out-of-home activities. Big data can advance the identification of activity spaces and the understanding of spatial equity. Using the Los Angeles metropolitan area for the case study, this paper employs geotagged Twitter data to delineate activity spaces with two spatial measures: first, the average distance between users’ home location and activity locations; and second, the area covered between home and activity locations. The paper also finds significant relationship between the spatial measures of activity spaces and neighborhood spatial and socioeconomic characteristics. This research enriches the literature that aims to address spatial equity in activity spaces and demonstrates the applicability of big data in urban socio-spatial research. Numéro de notice : A2020-135 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/15230406.2019.1705187 Date de publication en ligne : 10/02/2020 En ligne : https://doi.org/10.1080/15230406.2019.1705187 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94843 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
032-2020031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Estimating spatial efficiency using cyber search, GIS, and spatial optimization: a case study of fire service deployment in Los Angeles County / R.L. Church in International journal of geographical information science IJGIS, vol 30 n° 3-4 (March - April 2016)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 30 n° 3-4 (March - April 2016) . - pp 535 - 553 Titre : Estimating spatial efficiency using cyber search, GIS, and spatial optimization: a case study of fire service deployment in Los Angeles County Type de document : Article/Communication Auteurs : R.L. Church, Auteur ; Wenwen Li, Auteur Année de publication : 2016 Article en page(s) : pp 535 - 553 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] couverture (données géographiques) [Termes IGN] évaluation [Termes IGN] Los Angeles [Termes IGN] lutte contre l'incendie [Termes IGN] optimisation spatiale [Termes IGN] précision de localisation [Termes IGN] système d'information géographique Résumé : (Auteur) The efficiency of public investments and services has been of interest to geographic researchers for several decades. While in the private sector inefficiency often leads to higher prices, loss of competitiveness, and loss of business, in the public sector inefficiency in service provision does not necessarily lead to immediate changes. In many cases, it is not an entirely easy task to analyze a particular service as appropriate data may be difficult to obtain and hidden in detailed budgets. In this paper, we develop an integrative approach that uses cyber search, Geographic Information System (GIS), and spatial optimization to estimate the spatial efficiency of fire protection services in Los Angeles (LA) County. We develop a cyber-search process to identify current deployment patterns of fire stations across the major urban region of LA County. We compare the results of our search to existing databases. Using spatial optimization, we estimate the level of deployment that is needed to meet desired coverage levels based upon the location of an ideal fire station pattern, and then compare this ideal level of deployment to the existing system as a means of estimating spatial efficiency. GIS is adopted throughout the paper to simulate the demand locations, to conduct location-based spatial analysis, to visualize fire station data, and to map model simulation results. Finally, we show that the existing system in LA County has considerable room for improvement. The methodology presented in this paper is both novel and groundbreaking, and the automated assessments are readily transferable to other counties and jurisdictions. Numéro de notice : A2016--062 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2015.1083572 En ligne : https://doi.org/10.1080/13658816.2015.1083572 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79890 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2016021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Finding shortest paths on real road networks: the case for A* / W. Zeng in International journal of geographical information science IJGIS, vol 23 n°3-4 (march - april 2009)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 23 n°3-4 (march - april 2009) . - pp 531 - 543 Titre : Finding shortest paths on real road networks: the case for A* Type de document : Article/Communication Auteurs : W. Zeng, Auteur Année de publication : 2009 Article en page(s) : pp 531 - 543 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] chemin le plus court, algorithme du [Termes IGN] Los Angeles [Termes IGN] méthode heuristique [Termes IGN] réseau de transport [Termes IGN] réseau routier [Termes IGN] système d'information géographique Résumé : (Auteur) The problem of identifying the shortest path along a road network is a fundamental problem in network analysis, ranging from route guidance in a navigation system to solving spatial allocation problems. Since this type of problem is solved so frequently, it is important to craft an approach that is as efficient as possible. Based upon past research, it is generally accepted that several efficient implementations of the Dijkstra algorithm are the fastest at optimally solving the 'one-to-one' shortest path problem (Cherkassky et al. 1996). We show that the most efficient state-of-the-art implementations of Dijkstra can be improved by taking advantage of network properties associated with GIS-sourced data. The results of this paper, derived from tests of different algorithmic approaches on real road networks, will be extremely valuable for application developers and researchers in the GIS community. Copyright Taylor & Francis Numéro de notice : A2009-162 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810801949850 En ligne : https://doi.org/10.1080/13658810801949850 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29792 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-09021	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-09022	RAB	Revue	Centre de documentation	En réserve L003	Disponible

A new method for the specification of geographic footprints in digital gazetteers / J.P. Wilson in Cartography and Geographic Information Science, vol 31 n° 4 (October 2004)  

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Assessing vulnerability to earthquake hazards through spatial multicriteria analysis of urban areas / T. Rashed in International journal of geographical information science IJGIS, vol 17 n° 6 (september 2003)  

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Measuring the physical composition of urban morphology using multiple endmember spectral mixture models / T. Rashed in Photogrammetric Engineering & Remote Sensing, PERS, vol 69 n° 9 (September 2003)  

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Satellite multi-sensor data analysis of urban surface temperatures and Landcover / B. Dousset in ISPRS Journal of photogrammetry and remote sensing, vol 58 n° 1-2 (June - December 2003)  

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Satellite-derived urban heat islands from three coastal cities and the utilization of such data in urban climatology / M. Roth in International Journal of Remote Sensing IJRS, vol 10 n° 11 (November 1989)  

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Detecting air pollution stress in southern California vegetation using Landsat Thematic Mapper band data / W.E. Westman in Photogrammetric Engineering & Remote Sensing, PERS, vol 54 n° 9 (september 1988)  

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Seasat synthetic aperture radar views Los-Angeles / M.L. Bryan in Photo interprétation, vol 1981 n° 5 (Septembre 1981)

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