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Identification of enclaves and exclaves by computation based on point-set topology / Xiaonan Wang in International journal of geographical information science IJGIS, vol 37 n° 2 (February 2023)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 37 n° 2 (February 2023) . - pp 307 - 338 Titre : Identification of enclaves and exclaves by computation based on point-set topology Type de document : Article/Communication Auteurs : Xiaonan Wang, Auteur Année de publication : 2023 Article en page(s) : pp 307 - 338 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] frontière [Termes IGN] géopolitique [Termes IGN] intersection spatiale [Termes IGN] partition de surface [Termes IGN] polygone [Termes IGN] relation topologique [Termes IGN] territoire [Termes IGN] topologie Résumé : (auteur) Enclaves and exclaves have special roles in geography and are of particular importance to fields such as (geo)politics and economy. However, enclaves and exclaves have not been defined with sufficient formality for automatic identification yet. To identify enclaves and exclaves more generally by computational means than current definitions existing in the literature, this article proposes expressive and generalized mathematical definitions of enclaves and exclaves based on point-set topology. A novel Boundary Extended 16-Intersection Model is developed in this article to identify enclaves, and 74 possible spatial configurations of enclaves are distinguished according to conditions of intersections for polygons in partitions and enclaves. The classic Dimensionally Extended 9-Intersection Model is employed to identify exclaves, and two possible spatial configurations of exclaves are distinguished according to conditions of intersections for polygons in partitions and exclaves. Applications of the proposed definitions are exemplified by the identification of enclaves and exclaves in prototypes and in the real world. Numéro de notice : A2023-102 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2022.2120995 Date de publication en ligne : 21/09/2022 En ligne : https://doi.org/10.1080/13658816.2022.2120995 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102428 [article]

Simultaneous & topologically-safe line simplification for a variable-scale planar partition / Martijn Meijers (31/01/2011) 

Public contenu dans Advancing geoinformation science for a changing world / Stan Geertman (2011)   Titre : Simultaneous & topologically-safe line simplification for a variable-scale planar partition Type de document : Article/Communication Auteurs : Martijn Meijers, Auteur Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 31/01/2011 Conférence : AGILE 2011, 14th International Conference on Geographic Information Science, Advancing Geoinformation Science for a Changing World 18/04/2011 21/04/2011 Utrecht Pays-Bas Proceedings Springer Importance : pp 337 - 358 Format : 21 x 30 cm Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] généralisation automatique de données [Termes IGN] graphe planaire [Termes IGN] lissage de courbe [Termes IGN] partition de surface [Termes IGN] simplification de contour [Vedettes matières IGN] Généralisation Résumé : (Auteur) We employ a batch generalization process for obtaining a variable-scale planar partition. We describe an algorithm to simplify the boundary lines after a map generalization operation (either a merge or a split operation) has been applied on a polygonal area and its neighbours. The simplification is performed simultaneously on the resulting boundaries of the new polygonal areas that replace the areas that were processed. As the simplification strategy has to keep the planar partition valid, we define what we consider to be a valid planar partition (among other requirements, no zero-sized areas and no unwanted intersections in the boundary polylines). Furthermore, we analyse the effects of the line simplification for the content of the data structures in which the planar partition is stored. Numéro de notice : C2011-023 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=64364

Documents numériques

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An adaptive approach to selecting a flow-partition exponent for a multiple-flow-direction algorithm / C. Qin in International journal of geographical information science IJGIS, vol 21 n° 3-4 (march - april 2007)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 21 n° 3-4 (march - april 2007) . - pp 443 - 458 Titre : An adaptive approach to selecting a flow-partition exponent for a multiple-flow-direction algorithm Type de document : Article/Communication Auteurs : C. Qin, Auteur ; A - Xing Zhu, Auteur ; Tao Pei, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 443 - 458 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes IGN] bassin hydrographique [Termes IGN] Chine [Termes IGN] flux [Termes IGN] modèle numérique de surface [Termes IGN] partition de surface [Termes IGN] système d'information géographique Résumé : (Auteur) Most multiple-flow-direction algorithms (MFDs) use a flow-partition coefficient (exponent) to determine the fractions draining to all downslope neighbours. The commonly used MFD often employs a fixed exponent over an entire watershed. The fixed coefficient strategy cannot effectively model the impact of local terrain conditions on the dispersion of local flow. This paper addresses this problem based on the idea that dispersion of local flow varies over space due to the spatial variation of local terrain conditions. Thus, the flow-partition exponent of an MFD should also vary over space. We present an adaptive approach for determining the flow-partition exponent based on local topographic attribute which controls local flow partitioning. In our approach, the influence of local terrain on flow partition is modelled by a flow-partition function which is based on local maximum downslope gradient (we refer to this approach as MFD based on maximum downslope gradient, MFD-md for short). With this new approach, a steep terrain which induces a convergent flow condition can be modelled using a large value for the flow-partition exponent. Similarly, a gentle terrain can be modelled using a small value for the flow-partition exponent. MFD-md is quantitatively evaluated using four types of mathematical surfaces and their theoretical 'true' value of Specific Catchment Area (SCA). The Root Mean Square Error (RMSE) shows that the error of SCA computed by MFD-md is lower than that of SCA computed by the widely used SFD and MFD algorithms. Application of the new approach using a real DEM of a watershed in Northeast China shows that the flow accumulation computed by MFD-md is better adapted to terrain conditions based on visual judgement. Copyright Taylor & Francis Numéro de notice : A2007-120 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810601073240 En ligne : https://doi.org/10.1080/13658810601073240 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28483 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-07021	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-07022	RAB	Revue	Centre de documentation	En réserve L003	Disponible

A split-and-merge technique for automated reconstruction of roof planes / Kourosh Khoshelham in Photogrammetric Engineering & Remote Sensing, PERS, vol 71 n° 7 (July 2005)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 71 n° 7 (July 2005) . - pp 855 - 862 Titre : A split-and-merge technique for automated reconstruction of roof planes Type de document : Article/Communication Auteurs : Kourosh Khoshelham, Auteur ; Z. Li, Auteur ; B. King, Auteur Année de publication : 2005 Article en page(s) : pp 855 - 862 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes IGN] extraction du sursol [Termes IGN] hauteur du bâti [Termes IGN] modèle numérique de surface [Termes IGN] morphologie urbaine [Termes IGN] partition de surface [Termes IGN] reconstruction 3D du bâti [Termes IGN] segmentation d'image Résumé : (Auteur) Automated reconstruction of buildings from different data sources has been one of the most challenging problems in photogrammetry and computer vision. Systems for automated building reconstruction fail in many cases due to complexities involved in the data including image noise, occlusion, shadow, and low contrast, as well as, low accuracy or density of height data. In this paper, the problem of overgrown and undergrown regions in the segmentation of aerial images is discussed, and a split-and-merge technique is presented to overcome this problem by making use of height data. This technique is based on splitting image regions whose associated height points do not fall in a single plane, and merging coplanar neighboring regions. A robust plane-fitting method is used to fit planar surfaces to height points that are highly contaminated by gross errors. Final roof planes are extracted out of the image planar regions by checking their slope and height over a morphologically opened Dsm. An experimental evaluation is conducted, and its results indicate the capability of the proposed technique in splitting overgrown regions, merging undergrown coplanar regions, and selecting the final roof planes. Also, the method is shown to be computationally efficient, and the reconstructed roof planes are of acceptable accuracy. Numéro de notice : A2005-300 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.71.7.855 En ligne : https://doi.org/10.14358/PERS.71.7.855 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27436 [article]

Technological aspects of a full 3D cadastral registration / Jantien E. Stoter in International journal of geographical information science IJGIS, vol 19 n° 6 (july 2005)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 19 n° 6 (july 2005) . - pp 669 - 696 Titre : Technological aspects of a full 3D cadastral registration Type de document : Article/Communication Auteurs : Jantien E. Stoter, Auteur ; Peter J. M. Van Oosterom, Auteur Année de publication : 2005 Article en page(s) : pp 669 - 696 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cadastre étranger [Termes IGN] cadastre étranger [Termes IGN] modèle conceptuel de données localisées [Termes IGN] modèle numérique de surface [Termes IGN] modélisation 3D [Termes IGN] objet géographique 3D [Termes IGN] Oracle spatial [Termes IGN] partition de surface [Termes IGN] polyèdre [Termes IGN] prototype [Termes IGN] Queensland (Australie) [Termes IGN] système d'information foncière [Termes IGN] Triangulated Irregular Network Résumé : (Auteur) In this paper, we present a new conceptual model for a full 3D cadastral registration system. Two important components are : (1) the "surface parcel partition" based on a detailed elevation model and (2) the volume parcel and its representation. Technological solutions for both parts are not yet available in commercial Geo-ICT software, and therefore solutions have been investigated, designed and developed (in a geo-DBMS environment). A number of countries in the world do already have legislation allowing the registration of volume parcels, sometimes even including detailed regulations for 3D survey plans. However, until now, these have not yet been integrated in the cadastral information system. A 3D case from Queensland, Australia is presented, and a prototype is realized based on an integrated 3D cadastral information system : elevation-model-based surface parcels complemented with volume parcels. Numéro de notice : A2005-288 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810500106042 En ligne : https://doi.org/10.1080/13658810500106042 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27424 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-05061	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-05062	RAB	Revue	Centre de documentation	En réserve L003	Disponible

vol 64 n° 2 - March 2002 - Ninth Pacific graphics conference (PG 2001), [actes], Tokyo, 16 - 18 October 2001 (Bulletin de Graphical models) / H. Suzuki

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