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A discussion on the computational limitations of outranking methods for land-use suitability assessment / O. Marinoni in International journal of geographical information science IJGIS, vol 20 n° 1 (january 2006)
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Titre : A discussion on the computational limitations of outranking methods for land-use suitability assessment Type de document : Article/Communication Auteurs : O. Marinoni, Auteur Année de publication : 2006 Article en page(s) : pp 69 - 87 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] analyse multicritère
[Termes IGN] base de données localisées
[Termes IGN] données maillées
[Termes IGN] itération
[Termes IGN] outil d'aide à la décision
[Termes IGN] système d'information géographique
[Termes IGN] utilisation du solRésumé : (Auteur) The family of outranking methods includes a set of well-known and popular decision-aid methods. Heterogeneous variables of various scales can be introduced, and data transformations are not required. But it is also recognized that these methods are subject to computational limitations with respect to the number of decision alternatives. Dealing with large raster datasets and considering every raster cell a location alternative, these methods reach their computational limits quickly. This paper discusses these computational limits and presents an iterative approach which enables a modeller to easily and transparently apply outranking methods for land-suitability assessment with practically no limit in the sizes of the raster datasets. An example using the PROMETHEE outranking approach is performed. Numéro de notice : A2006-026 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810500287040 En ligne : https://doi.org/10.1080/13658810500287040 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27753
in International journal of geographical information science IJGIS > vol 20 n° 1 (january 2006) . - pp 69 - 87[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-06011 RAB Revue Centre de documentation En réserve L003 Disponible 079-06012 RAB Revue Centre de documentation En réserve L003 Disponible Extraction of tidal channel networks from aerial photographs alone and combined with laser altimetry / Bharat Lohani in International Journal of Remote Sensing IJRS, vol 27 n°1-2 (January 2006)
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Titre : Extraction of tidal channel networks from aerial photographs alone and combined with laser altimetry Type de document : Article/Communication Auteurs : Bharat Lohani, Auteur ; D.C. Mason, Auteur ; T.R. Scott, Auteur ; B. Sreenivas, Auteur Année de publication : 2006 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] détection de contours
[Termes IGN] données lidar
[Termes IGN] fusion d'images
[Termes IGN] fusion de données
[Termes IGN] identification automatique
[Termes IGN] image multibande
[Termes IGN] marais salé
[Termes IGN] océanographie dynamique
[Termes IGN] sédimentationRésumé : (Auteur) Tidal channel networks play an important role in the intertidal zone, exerting substantial control over the hydrodynamics and sediment transport of the region and hence over the evolution of the salt marshes and tidal flats. The study of the morphodynamics of tidal channels is currently an active area of research, and a number of theories have been proposed which require for their validation measurement of channels over extensive areas. Remotely sensed data provide a suitable means for such channel mapping. The paper describes a technique that may be adapted to extract tidal channels from either aerial photographs or LiDAR data separately, or from both types of data used together in a fusion approach. Application of the technique to channel extraction from LiDAR data has been described previously. However, aerial photographs of intertidal zones are much more commonly available than LiDAR data, and most LiDAR flights now involve acquisition of multispectral images to complement the LiDAR data. In view of this, the paper investigates the use of multispectral data for semiautomatic identification of tidal channels, firstly from only aerial photographs or linescanner data, and secondly from fused linescanner and LiDAR data sets. A multi-level, knowledge-based approach is employed. The algorithm based on aerial photography can achieve a useful channel extraction, though may fail to detect some of the smaller channels, partly because the spectral response of parts of the non-channel areas may be similar to that of the channels. The algorithm for channel extraction from fused LiDAR and spectral data gives an increased accuracy, though only slightly higher than that obtained using LiDAR data alone. The results illustrate the difficulty of developing a fully automated method, and justify the semi-automatic approach adopted. Numéro de notice : A2006-058 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160500206692 En ligne : https://doi.org/10.1080/01431160500206692 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27785
in International Journal of Remote Sensing IJRS > vol 27 n°1-2 (January 2006)[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 080-06011 RAB Revue Centre de documentation En réserve L003 Disponible Fourier series and the cartographic line / G.J. Lawford in International journal of geographical information science IJGIS, vol 20 n° 1 (january 2006)
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Titre : Fourier series and the cartographic line Type de document : Article/Communication Auteurs : G.J. Lawford, Auteur Année de publication : 2006 Article en page(s) : pp 31 - 52 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] Australie
[Termes IGN] données vectorielles
[Termes IGN] échelle cartographique
[Termes IGN] généralisation cartographique automatisée
[Termes IGN] matrice
[Termes IGN] reconnaissance de formes
[Termes IGN] segment de droite
[Termes IGN] série de Fourier
[Termes IGN] simplification de contour
[Termes IGN] système d'information géographique
[Termes IGN] trait de côte
[Termes IGN] transformation de FourierRésumé : (Auteur) The application of Fourier Series to cartography and GIS, in particular to shape analysis, fine simplification and enhancement, and the measurement of cartographic scale, is explored. Vector representations of the Australian coastline are manipulated using Fourier techniques and the output appraised in terms of its ability to encapsulate the shape of the original coastline, or as a simplified or enhanced version of the original. Using Fourier techniques on vector representations of parts of the Australian coastline at six different cartographic scales, a relationship between cartographic scale and line complexity is found to exist, and an empirical expression of that relationship developed. The intent of developing an empirical relationship is to bring greater consistency to the process of assigning cartographic scale to data, and thereby to the process of map production, data simplification and GIS analysis. Fourier techniques are found to be a poor encapsulator of cartographic shape, a good method of line simplification and enhancement, and a promising method of measuring cartographic scale. As background, some revision of the history and mathematics of Fourier Series, and previous research into the application of Fourier Series to cartography, is given. Numéro de notice : A2006-024 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1080/13658810512331319109 En ligne : https://doi.org/10.1080/13658810512331319109 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27751
in International journal of geographical information science IJGIS > vol 20 n° 1 (january 2006) . - pp 31 - 52[article]Réservation
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Titre : Geo-information and computational geometry Type de document : Monographie Auteurs : Peter J. M. Van Oosterom, Éditeur scientifique ; Marc J. Van Kreveld, Éditeur scientifique Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 2006 Collection : Netherlands Geodetic Commission Green series num. 44 Importance : 51 p. Format : 17 x 24 cm ISBN/ISSN/EAN : 978-90-6132-299-3 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] analyse spatiale
[Termes IGN] détection du bâti
[Termes IGN] données lidar
[Termes IGN] données localisées
[Termes IGN] données topographiques
[Termes IGN] géomètrie algorithmique
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] reconstruction 3D du bâti
[Termes IGN] système d'information géographiqueRésumé : (Editeur) The contributions reflect the diversity of the possible interactions between computational geometry and GIS. The topics of the contributions range from overviews of relevant techniques and tools to solving specific spatial problems in either the object-based (vector) or field-based (raster) domain. This publication is a reflection of the different seminar contributions. The first paper 'Computational Geometry: its objectives and relation to GIS' is by Marc van Kreveld (Utrecht University). The analysis of algorithms involves understanding how efficiently an algorithm solves a problem. One of the main objectives of computational geometry is finding the most efficient algorithms for all sorts of geometric problems. He introduces the main concepts and ideas in computational geometry, including efficiency analysis, intractability, output-sensitive algorithms, and approximation algorithms. The basic problems of computational geometry all have a direct or indirect use to GIS. He also indicates why computational geometry is not as useful to GIS as it could be (complicated algorithms, focus on worst-case efficiency, and on well-defined, simple to state problems) and how this is currently improving (available software libraries, simpler algorithms provably efficient under realistic assumptions).
Mark de Berg (TU Eindhoven) addresses one of the issues to make computational geometry techniques more applicable in practice, namely the handling of large data sets that do not fit in main memory (as often more or less implicitly assumed in the description of many data structures and algorithms). In his paper 'I/O- and Cache-efficient Algorithms for Spatial Data', he explains how the hierarchical memory consisting of a disk, main memory, and several levels of cache should be included in data structure and algorithm design. The difference between the times to access these different levels of memory is quite large: the disk is typically about 100,000 times slower than accessing the main memory. In the paper some of the recent results that have been obtained on I/O- and cache-efficient algorithms are discussed with focus on spatial data.
One specific data structure, based on quad-edges, and applied to creating and editing three-dimensional models, is described by Christopher Gold and Rebecca Tse (University of Glamorgan, UK) in their paper 'Quad-Edges and Euler Operators for Automatic Building Extrusion Using LiDAR Data' (LIght Detection And Ranging). The long-term research objective for their models is to integrate man-made objects with the landscape, so that topological properties, such as connectedness, may be used in applications such as flood modeling. Man-made objects such as build-ings, as well as terrain elevation, should be extracted directly from LiDAR data. Their model is a triangle-based boundary description of the relevant objects and earth surface. The model creation and local modifications (updates) is performed on the Quad-Edge data structure by using Euler operators. These operators permit various extrusion operations as well as the manual insertion of bridges and tunnels.
A description of the use computational geometry tools used to solve a few specific cartographic problems is given by Bettina Speckmann (TU Eindhoven) in her paper 'Algorithms for cartograms and other specialized maps'. Cartograms are a useful and intuitive tool to visualize statistical data about a set of regions like countries, states or counties. The size of a region in a cartogram corresponds to a particular geographic variable and therefore the regions generally cannot keep both their shape and their adjacencies. A good cartogram, however, preserves the recognizability in some way. The paper gives a short overview of cartogram algorithms, and focuses in particular on the computation of rectangular cartograms. In a rectangular cartogram each region is represented by a rectangle. An implementation and various tests show that in practice, visually pleasing rectangular cartograms with small cartographic error can be generated effectively. Furthermore, the computation of proportional symbol maps is also discussed briefly.
Three-dimensional topographic modeling is also the topic of the paper by Friso Penninga (TU Delft): 'Constrained tetrahedral models and update algorithms for topographic data'. In contrast to the work of Gold and Tse he does not do this by representing the bounding surfaces, but he represents the three-dimensional objects by sets of tetrahedrons. The whole model then becomes a tetrahedronized irregular network (TEN), the 3D version of the more generally known triangulated irregular network (TIN). The TEN is a well-defined and robust data structure which enables complex processing by separate processing on each primitive first and afterwards joining all these partial results into a final result. In order to represent their borders several edges and faces will be handled as constraints. Updating a topographic dataset therefore equals the addition and removal of constraints within the network. One of the biggest challenges in the realization of such a data structure and corresponding algorithms is to reach acceptable performance, despite the potentially enormous amount of data. The last paper 'Towards improved solution schemes for Monte Carlo simulation in environmental modeling languages' is by Derek Karssenberg and Kor de Jong (Utrecht University). They deal with the field-based representation of spatial data, in contrast to the object-based representation of spatial data in the other papers. On the most often used field-based data structure, the regular grid, the algorithmic challenges are quite different than their counterparts in the object-based approaches. Environmental modeling languages such as PCRaster are programming languages embedded in GIS to simulate environmental processes. These languages are used to construct dynamic models, also called forward models, which are simulations run forward in time, where the state of the model at time t is defined as a function of its state in a time step preceding t. For future applications, at least two extensions to the languages are required: support of three spatial dimensions (as the real world is often 3D), and inclusion of Monte Carlo simulation techniques (to calculate how input errors propagate to the output of a model).Note de contenu : Editorial - Peter van Oosterom and Marc van Kreveld
- Computational Geometry: Ils objectives and relation to GIS - Marc van Kreveld
- I/O- and Cache-Efficient Algorithms for Spatial Data - Mark de Berg
- Quad-Edges and Euler Operators for Automatic Building Extrusion Using LIDAR Data - Christopher
Gold and Rebecca Tse
- Algorithms for cartograms and other specialized maps - Bettina Speckmann
- Constrained tetrahedral models and update algorithms for topographie data - Friso Penninga
- Towards improved solution schemes for Monte Carlo simulation in environmental modeling languages - Derek Karssenberg and Kor de JongNuméro de notice : 15213 Affiliation des auteurs : non IGN Autre URL associée : téléchargement Thématique : GEOMATIQUE Nature : Recueil / ouvrage collectif DOI : sans En ligne : https://www.ncgeo.nl/index.php/en/publicatiesgb/green-series/item/2363-gs-44-pet [...] Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55100 Réservation
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Geo-information and computational geometry - pdf éditeurAdobe Acrobat PDFHochgenaue Generierung des DGM vom vergletscherten Hochgebirge : Potential von airborne Laserscanning / D. Lenhart (2006)
contenu dans Arbeitsgruppe "Automation inder Kartographie", Tagung 2005 / Bundesamt für Kartographie und Geodäsie (2006)
Titre : Hochgenaue Generierung des DGM vom vergletscherten Hochgebirge : Potential von airborne Laserscanning Titre original : [Génération de haute précision de MNT de hautes montagnes couvertes de glaciers : potentiel de la télémétrie laser aéroporté] Type de document : Article/Communication Auteurs : D. Lenhart, Auteur ; H. Kager, Auteur ; Konrad Eder, Auteur ; Stefan Hinz, Auteur ; U. Stella, Auteur Editeur : Francfort sur le Main : Bundesamt für Kartographie und Geodäsie Année de publication : 2006 Conférence : Arbeitsgruppe Automation in der Kartographie, Tagung 2005 Vienne Autriche Importance : pp 65 - 78 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] données laser
[Termes IGN] glacier
[Termes IGN] lasergrammétrie
[Termes IGN] modèle numérique de terrain
[Termes IGN] montagne
[Termes IGN] neige
[Termes IGN] semis de pointsRésumé : (Auteur) Le système de scannage par Laser aéroporté (ALS/Airborne Laserscanning) offre la possibilité de générer des modèles de terrain numériques (MTN) avec un haut degré d'automatisation. Pendant que le potentiel de précision inhérent à cette technologie a déjà été mis à l'épreuve dans beaucoup d'études et d'applications, le présent article analyse le potentiel de précision de cette méthode lorsqu'elle est appliquée en haute montagne couverte de glaciers. Les résultats montrent qu'au moyen d'un géoréférencement par voie d'adaptation simultanée de bandes avoisinantes, non seulement les différences existant entre des bandes longitudinales peuvent être minimisées, mais aussi les données peuvent être rattachées jusqu'à quelques centimètres à l'information GPS de référence. Ainsi, la précision intérieure est de l'ordre de 5-8 cm pour des régions lisses telles que des surfaces de neige, et d'environ 17-30 cm pour les régions rocheuses rugueuses. En dehors de la haute précision, c'est la densité de points du jeu de données qui offre un aspect intéressant d'analyse. Par exemple, des pertes partielles d'enregistrements - normalement nuisibles à un DGM - dans la région de la langue glacière (dues à l'absorption et probablement aussi à la réflexion régulière) ouvrent de nouvelles possibilités d'études telles que l'estimation locale du contenu d'eau, de glace ou de névé, ou aussi la reconnaissance automatique de limites de glaciers ou de névés. Numéro de notice : C2005-002 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Communication DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=65029 Improving building footprints in InSAR data comparison with a Lidar DSM / Paolo Gamba in Photogrammetric Engineering & Remote Sensing, PERS, vol 72 n° 1 (January 2006)
PermalinkMise en place d'un outil de contrôle de saisie des données vectorielles avec GIS Data Reviewer / N. Rakotobe (2006)
PermalinkRecognition of Building Roof Facets by Merging Aerial Images and 3D Lidar Data in a Hierarchical Segmentation Framework / Frédéric Bretar (2006)
PermalinkPermalinkSensitivity analysis and uncertainty analysis for vector geographical applications / Olivier Bonin (2006)
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PermalinkPermalinkSimulations numériques de mesures laser de distance entre la Terre et une sonde en orbite autour de Mars, amélioration de la détermination du champ de gravité de la planète / Jonathan Renault (2006)
PermalinkPermalinkUtilisation conjointe de données image et laser pour la segmentation et la modélisation 3D / Matthieu Deveau (2006)
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