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An ensemble approach to space-time interpolation / E. Wentz in International journal of geographical information science IJGIS, vol 24 n° 9 (september 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n° 9 (september 2010) . - pp 1309 - 1325 Titre : An ensemble approach to space-time interpolation Type de document : Article/Communication Auteurs : E. Wentz, Auteur ; Donna J. Peuquet, Auteur ; S. Anderson, Auteur Année de publication : 2010 Article en page(s) : pp 1309 - 1325 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse spatio-temporelle [Termes IGN] estimation statistique [Termes IGN] implémentation (informatique) [Termes IGN] interpolation [Termes IGN] milieu urbain [Termes IGN] occupation du sol [Termes IGN] paramètre de temps [Termes IGN] Phoenix [Termes IGN] urbanisation Résumé : (Auteur) The availability of spatial data on an unprecedented scale as well as advancements in analytical and visualization techniques gives researchers the opportunity to study complex problems over large urban and regional areas. Nevertheless, few individual data sets exist that provide both the requisite spatial and/or temporal observational frequency to truly facilitate detailed investigations. Some data are collected frequently over time but only at a few geographic locations (e.g., weather stations). Similarly, other data are collected with a high level of spatial resolution but not at regular or frequent time intervals (e.g., satellite data). The purpose of this article is to present an interpolation approach that leverages the relative temporal richness of one data set with the relative spatial richness of another to fill in the gaps. Because different interpolation techniques are more appropriate than others for specific types of data, we propose a space-time interpolation approach whereby two interpolation methods - one for the temporal and one for the spatial dimension - are used in tandem to increase the accuracy results. We call our ensemble approach the space-time interpolation environment (STIE). The primary steps within this environment include a spatial interpolation processor, a temporal interpolation processor, and a calibration processor, which enforces phenomenon-related behavioral constraints. The specific interpolation techniques used within the STIE can be chosen on the basis of suitability for the data and application at hand. In this article, we first describe STIE conceptually including the data input requirements, output structure, details of the primary steps, and the mechanism for coordinating the data within those steps. We then describe a case study focusing on urban land cover in Phoenix, Arizona, using our working implementation. Our empirical results show that our approach increased the accuracy for estimating urban land cover better than a single interpolation technique. Numéro de notice : A2010-404 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/URBANISME Nature : Article DOI : 10.1080/13658816.2010.488238 En ligne : https://doi.org/10.1080/13658816.2010.488238 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30597 [article]

Exemplaires(2)

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079-2010052	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Directed movements in probabilistic time geography / Stephan Winter in International journal of geographical information science IJGIS, vol 24 n° 9 (september 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n° 9 (september 2010) . - pp 1349 - 1365 Titre : Directed movements in probabilistic time geography Type de document : Article/Communication Auteurs : Stephan Winter, Auteur ; Z. Yin, Auteur Année de publication : 2010 Article en page(s) : pp 1349 - 1365 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse spatio-temporelle [Termes IGN] cône [Termes IGN] distribution, loi de [Termes IGN] incertitude des données [Termes IGN] modèle stochastique [Termes IGN] prisme [Termes IGN] Time-geography Résumé : (Auteur) This article studies probabilistic time geography for space-time prisms, that is, for situations where observers know the location of an agent at one time and then again at another time. In the intervening period, the agent would have moved freely, according to its time budget. The article demonstrates that the probability of finding the agent somewhere in the space-time prism is not equally distributed, so any attempt of a quantitative time geographic analysis must consider the actual probability distribution. This article develops, implements, and demonstrates this distribution. A preceding article introduced probabilistic time geography for space-time cones. With cones and prisms, the elementary space-time volumes of time geography are provided. Numéro de notice : A2010-405 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658811003619150 En ligne : https://doi.org/https://doi.org/10.1080/13658811003619150 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30598 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2010051	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2010052	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Local entropy map : a nonparametric approach to detecting spatially varying multivariate relationships / D. Guo in International journal of geographical information science IJGIS, vol 24 n° 9 (september 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n° 9 (september 2010) . - pp 1367 - 1389 Titre : Local entropy map : a nonparametric approach to detecting spatially varying multivariate relationships Type de document : Article/Communication Auteurs : D. Guo, Auteur Année de publication : 2010 Article en page(s) : pp 1367 - 1389 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse multivariée [Termes IGN] entropie [Termes IGN] régression linéaire [Termes IGN] relation spatiale [Termes IGN] variable Résumé : (Auteur) The relationship between two or more variables may change over the geographic space. The change can be in parameter values (e.g., regression coefficients) or even in relation forms (e.g., linear, quadratic, or exponential). Existing local spatial analysis methods often assume a relationship form (e.g., a linear regression model) for all regions and focus only on the change in parameter values. Therefore, they may not be able to discover local relationships of different forms simultaneously. This research proposes a nonparametric approach, a local entropy map, which does not assume a prior relationship form and can detect the existence of multivariate relationships regardless of their forms. The local entropy map calculates an approximation of the Rényi entropy for the multivariate data in each local region (in the geographic space). Each local entropy value is then converted to a p-value by comparing to a distribution of permutation entropy values for the same region. All p-values (one for each local region) are processed by several statistical tests to control the multiple-testing problem. Finally, the testing results are mapped and allow analysts to locate and interactively examine significant local relationships. The method is evaluated with a series of synthetic data sets and a real data set. Numéro de notice : A2010-406 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658811003619143 En ligne : https://doi.org/10.1080/13658811003619143 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30599 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2010051	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2010052	RAB	Revue	Centre de documentation	En réserve L003	Disponible

GIS-augmented video surveillance / A. Milosavljevic in International journal of geographical information science IJGIS, vol 24 n° 9 (september 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n° 9 (september 2010) . - pp 1415 - 1433 Titre : GIS-augmented video surveillance Type de document : Article/Communication Auteurs : A. Milosavljevic, Auteur ; D. Rancic, Auteur ; A. Rancic, Auteur Année de publication : 2010 Article en page(s) : pp 1415 - 1433 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes IGN] caméra de surveillance PTZ [Termes IGN] réalité augmentée [Termes IGN] SIG 3D [Termes IGN] système d'information géographique [Termes IGN] vidéo numérique [Termes IGN] zone urbaine Résumé : (Auteur) Registration in augmented reality is a process that merges virtual objects generated by a computer with real-world images captured by a camera. In this article, we present a method for registration of geospatial data applicable to outdoor video surveillance systems consisting of several PTZ cameras. PTZ is an abbreviation for pan-tilt-zoom, and in the terminology of video surveillance it indicates cameras that can rotate in the horizontal (pan) and vertical planes (tilt) and change their level of magnification (zoom). Registration is based on transforming these relative camera view parameters into the absolute position, orientation and field of view required by the three-dimensional geographic information systems (3D GISs). Once the 3D GIS and camera views are aligned, it is possible to identify geospatial objects from the camera image, as well as to overlap the virtual scene with the real one. In addition, inverse transformation of the view parameters allows for selecting and pointing the appropriate camera to some geo-referenced feature or event. Based on the proposal, we developed GeoScopeAVS, a GIS-based system for augmented video surveillance and suggested application of such a system in emergency situation management and urban planning. Numéro de notice : A2010-407 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658811003792213 En ligne : https://doi.org/10.1080/13658811003792213 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30600 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2010051	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2010052	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Crossing natural and data set boundaries : coastal terrain modelling in the South-West Finnish Archipelago / A. Stock in International journal of geographical information science IJGIS, vol 24 n° 9 (september 2010)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 24 n° 9 (september 2010) . - pp 1435 - 1425 Titre : Crossing natural and data set boundaries : coastal terrain modelling in the South-West Finnish Archipelago Type de document : Article/Communication Auteurs : A. Stock, Auteur ; H. Tolvanen, Auteur ; R. Kalliola, Auteur Année de publication : 2010 Article en page(s) : pp 1435 - 1425 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes IGN] archipel [Termes IGN] eaux côtières [Termes IGN] Finlande [Termes IGN] frontière [Termes IGN] intégration de données [Termes IGN] littoral [Termes IGN] modèle numérique de terrain [Termes IGN] pente [Termes IGN] trait de côte Résumé : (Auteur) Geographical information systems (GIS) are important tools in coastal research and management. Coastal GIS applications involve special challenges, because the coastal environment is a complex transitional system between the terrestrial and marine realms. Also acquisition methods and responsibilities for spatial data (and thus their properties) change at the shoreline. This article explores the consequences of this land-sea divide for coastal terrain modelling. We study how methods designed for terrestrial environments can be used to create integrated raster coastal terrain models (CTMs) from coarse elevation and depth data. We focus on shore slopes, because many particularities of coastal terrain and the data which describe it as well as the resulting problems are concentrated in the shore zone. Based on shorelines, terrestrial contours, depth contours and depth points, we used the ANUDEM algorithm to interpolate CTMs at different spatial resolutions, with and without drainage enforcement, for two test areas in a highly complex archipelago coast. Slope aspect and gradient rasters were derived from the CTMs using Horn's algorithm. Values were assigned from the slope rasters to thousands of points along the test areas' shorelines in different ways. Shore slope gradients and aspects were also calculated directly from the shorelines and contours. These modelled data were compared to each other and to field-measured shore profiles using a combination of qualitative and quantitative methods. As far as the coarse source data permitted, the interpolation and slope calculations delivered good results at fine spatial resolutions. Vector-based slope calculations were very sensitive to quality problems of the source data. Fine-resolution raster data were consequently found most suitable for describing shore slopes from coarse coastal terrain data. Terrestrial and marine parts of the CTMs were subject to different errors, and modelling methods and parameters had different consequences there. Thus, methods designed for terrestrial applications can be successfully used for coastal terrain modelling, but the choice of methods and parameters and the interpretation of modelling results require special attention to the differences of terrestrial and marine topography and data. Numéro de notice : A2010-408 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658811003591698 En ligne : https://doi.org/10.1080/13658811003591698 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30601 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-2010051	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-2010052	RAB	Revue	Centre de documentation	En réserve L003	Disponible