Descripteur
Termes IGN > sciences naturelles > physique > traitement d'image > modèle numérique de terrain
modèle numérique de terrainSynonyme(s)MNT ;DTM DGMVoir aussi |
Documents disponibles dans cette catégorie (1042)
![](./images/expand_all.gif)
![](./images/collapse_all.gif)
Etendre la recherche sur niveau(x) vers le bas
Representing multiple spatial statistics in generalized elevation models: moving beyond the variogram / C. Ehlschlaeger in International journal of geographical information science IJGIS, vol 16 n° 3 (april 2002)
![]()
[article]
Titre : Representing multiple spatial statistics in generalized elevation models: moving beyond the variogram Type de document : Article/Communication Auteurs : C. Ehlschlaeger, Auteur Année de publication : 2002 Article en page(s) : pp 259 - 285 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] données localisées
[Termes IGN] incertitude géométrique
[Termes IGN] modèle d'incertitude
[Termes IGN] modèle de simulation
[Termes IGN] modèle numérique de surface
[Termes IGN] modèle numérique de terrain
[Termes IGN] variogrammeNuméro de notice : A2002-052 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1080/13658810110099116 En ligne : https://doi.org/10.1080/13658810110099116 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21969
in International journal of geographical information science IJGIS > vol 16 n° 3 (april 2002) . - pp 259 - 285[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 079-02031 RAB Revue Centre de documentation En réserve L003 Disponible Assessing effects of input uncertainty in structural landscape classification / Frank Canters in International journal of geographical information science IJGIS, vol 16 n° 2 (march 2002)
![]()
[article]
Titre : Assessing effects of input uncertainty in structural landscape classification Type de document : Article/Communication Auteurs : Frank Canters, Auteur ; W. De Genst, Auteur ; H. Dufourmont, Auteur Année de publication : 2002 Article en page(s) : pp 129 - 149 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] classification
[Termes IGN] incertitude géométrique
[Termes IGN] modèle d'erreur
[Termes IGN] modèle d'incertitude
[Termes IGN] modèle numérique de terrain
[Termes IGN] modélisation spatiale
[Termes IGN] paysage
[Termes IGN] simulationRésumé : (Auteur) This paper presents the results of a study aimed at assessing the effects of input uncertainty on the outcome of a raster-based model for structural landscape classification. The model uses a DEM and a land-cover map as input, and calculates four structural indices from these data. The first two indices determine the openness of the landscape, the other two determine the degree of landscape homogeneity. By combining both aspects, nine different landscape types are defined. Applying Monte Carlo simulation, the effect of DEM error, uncertainty in land-cover classification, and the combined effect of both sources of uncertainty on the outcome of the landscape model are assessed. Special attention is paid to the spatial structure of uncertainty in both data sources. Numéro de notice : A2002-024 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1080/13658810110099143 En ligne : https://doi.org/10.1080/13658810110099143 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21941
in International journal of geographical information science IJGIS > vol 16 n° 2 (march 2002) . - pp 129 - 149[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 079-02021 RAB Revue Centre de documentation En réserve L003 Disponible Contrôle de qualité des modèles numériques des bases de données géographiques / J.F. Zelasco in XYZ, n° 90 (mars - mai 2002)
[article]
Titre : Contrôle de qualité des modèles numériques des bases de données géographiques Type de document : Article/Communication Auteurs : J.F. Zelasco, Auteur Année de publication : 2002 Article en page(s) : pp 50 - 55 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique
[Termes IGN] base de données localisées
[Termes IGN] contrôle qualité
[Termes IGN] distance de Hausdorff
[Termes IGN] erreur moyenne quadratique
[Termes IGN] erreur moyenne quadratique altimétrique
[Termes IGN] modèle numérique de surface
[Termes IGN] modèle numérique de terrain
[Termes IGN] noeud
[Termes IGN] surface de référenceNuméro de notice : A2002-044 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21961
in XYZ > n° 90 (mars - mai 2002) . - pp 50 - 55[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 112-02011 RAB Revue Centre de documentation En réserve L003 Disponible Removing ridging in DTMs: lessons learned applying a quality control strategy / Kevin H. Pegler in GIM international, vol 16 n° 3 (March 2002)
[article]
Titre : Removing ridging in DTMs: lessons learned applying a quality control strategy Type de document : Article/Communication Auteurs : Kevin H. Pegler, Auteur ; David Coleman, Auteur Année de publication : 2002 Article en page(s) : pp 12 - 15 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] contrôle qualité
[Termes IGN] erreur de rendu
[Termes IGN] erreur géométrique
[Termes IGN] modèle numérique de terrainRésumé : (Auteur) Keepers of legacy datasets collected over the past few decades are under increasing pressure to allocate resources for the improvement of such datasets through reprocessing and the performance of even more stringent QC procedures. In response to this situation, Service New Brunswick (SNB) is reprocessing Digital Terrain Models (DTMs) datasets to remove the Ridging Effect. Ridging manifests itself as a series of unnatural crests and troughs. The authors review the Quality Control (QC) management model, QC specifications and the internal and external QC processes. Copyright GITC Numéro de notice : A2002-045 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21962
in GIM international > vol 16 n° 3 (March 2002) . - pp 12 - 15[article]Réservation
Réserver ce documentExemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 061-02031 RAB Revue Centre de documentation En réserve L003 Disponible
Titre : 3D terrain models on the basis of a triangulation Type de document : Thèse/HDR Auteurs : Norbert Pfeifer, Auteur Editeur : Vienne [Autriche] : Technische Universität Wien Année de publication : 2002 Collection : Geowissenschaftliche Mitteilungen, ISSN 1811-8380 num. 65 Importance : 142 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-9500791-7-3 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] données localisées 3D
[Termes IGN] interpolation
[Termes IGN] modèle numérique de terrain
[Termes IGN] noeud
[Termes IGN] reconstruction 3D
[Termes IGN] triangulation de DelaunayRésumé : (Auteur) This work provides an overview on terrain modelling techniques. Terrain models, or in order to be more general, topographic surface models, play an important role in many fields of science and practice where a relation to a location, i.e. a geo-relation' is given. These models describe the height as a function of the location. There lies a restriction in this definition, because only one height is allowed at one ground-plane position. Therefore, the currently used models are often termed 2.5D terrain models. The modelling of overhangs is not possible within such an approach. The aim of this work is to put aside this limitation and provide methods for 3D terrain modelling where not only the above restrictions do not apply anymore, but also more general surfaces with tunnels and cave systems can be reconstructed. Another terrain property which plays an important role in this work is its smoothness: a model shall be smooth. An exception is introduced at so-called breaklines where the terrain shape has a sharp edge.
There are several ways in order to build terrain models with the above characteristics (fully 3D and smooth). In this work, emphasis is put on those approaches which reconstruct the surface on the basis of a triangulation. Two different techniques are treated with great detail: the patch work and the subdivision approach. For each of those two, one method was developed which considers the special requirements in terrain modelling. The main contribution of this work to terrain modelling are those new methods. Generation, improvement, and thinning of triangulations is not treated within this work, but references to the relevant literature are given. Generally, the reconstruction of a patch work proceeds as follows. Given is a triangulation, which has as expected planar faces. For each edge a curve is determined which interpolates the end points. In the next step, triangular patches are inserted into a triple of boundary curves spanned over the edges of each triangle. As the patches interpolate the boundary curve a G0 surface (a geometrically continuous surface) is obtained.
However, this is not enough, because a smooth surface (G1, geometric continuity of order one, i.e. tangent plane continuity) is desired. Adjacent patches must therefore interpolate not only the boundary curves, but also share a common field of cross boundary derivatives. This is the general approach for patch work surfaces.
The patch work method which is proposed in this work1 starts with an enhancement of the triangulation. As the measurement of terrain points and lines is always burdened with random errors (depending on the measurement device characteristics) these errors should be removed first. This can be achieved by kriging, whereby for each point of the triangulation (i.e. each vertex) a filter value is determined from its neighboring points. In this step also the surface normal vectors in the points can be estimated, but alternative methods for the estimation of the normal vector, e.g. by averaging those of the triangles which are incident to that vertex, are possible, too. Now, not only the position, but also the surface normal vector is prescribed for each vertex. The patches which are to be reconstructed over each face of the triangulation shall be polynomials of degree four and they are described with Beziér triangles which allow a geometric interpretation of the coefficients of the (bivariate) polynomial. In the next step, boundary curves of polynomial degree three are computed which replace' the edges of the triangulation. These curves interpolate the end points of the edge and the curve tangents in those points are perpendicular to the estimated normal vectors. This determines the boundaries of each patch. The missing parameters (i.e. coefficients of the polynomial) influence the shape in the interior of the patch and also the tangent planes of the patch along the boundaries. A field of normal vectors is estimated for each boundary curve by blending the normal vectors from the end points into each other. The inner' parameters of a patch are now determined in a way that the normal vector fields are approximately perpendicular to the tangent planes of the patch along the boundaries in a least squares sense. As this field is only' approximated and not interpolated this scheme is called "G1 (i.e. approximately tangent plane continuous).
The second technique for surface reconstruction over a triangulation is the so-called subdivision. In this approach the given triangulation is refined in steps, and in each step new vertices and edges are inserted into the triangulation. This is performed in a way that the smoothness of the triangulation is increased in each level, the angles between adjacent triangles converge towards 180_. The limit surface, reached after an infinite number of subdivision steps, is smooth. An advantage of this approach is that the surface description is always composed of small triangles which allows to apply simple algorithms for intersections and similar tasks. The size of the triangles depends on the number of subdivision steps (i.e. the refinement level). This is the general approach for subdivision surfaces.
Also in the reconstruction technique (developed in this work) for topographic surfaces which is based on subdivision a removal of random measurement errors has to be performed first. The refinement rule applied here is the so-called edge midpoint subdivision where in one step one vertex is inserted into each edge and the triangulation is updated. The subdivision is based on the estimation of local surfaces in each vertex. A local surface is estimated which approximates the vertex of interest and its neighbors. The co-ordinates of the new points are obtained by averaging the two local surfaces in either edge end point. To achieve this, a point, representative for the edge midpoint, is computed on both local surfaces and the mean of these two is the new point. Also the old' points obtain new co-ordinates, namely their position on the local approximating surfaces. Special modifications are introduced in order to interpolate the originally given points. The approaches are compared to each other with examples based on real photogrammetric and geodetic observations as well as on synthetic terrain data. It turns out that the surfaces obtained by the developed subdivision approach meet the requirements in topographic terrain modelling better.Note de contenu : 1 Introduction
2 Modelling of Topographic Surfaces
2.1 Types of Models
2.1.1 Contour lines
2.1.2 Bivariate functions
2.1.3 Volumetric models
2.1.4 Transformation between models
2.2 Global and local approaches
2.3 Models in 2.5D and in 3D
2.4 3D terrain models
2.4.1 Problem definition
3 Algorithms for Triangulations
3.1 Definition of neighborhood
3.2 Parameterization of triangulations
3.2.1 Projection onto a plane
3.2.2 Local projection onto a plane
3.2.3 Global parameterizations
3.2.4 A method for local parameterization
3.3 Surface approximation and estimation of geometric properties
3.3.1 Normal vectors and tangent planes
3.3.2 Approximating quadric as local surface description
3.3.3 Approximating second order polynomial as local surface description
3.4 Functionals and variational principle
3.5 Mesh improvement
3.6 Filtering of random measurement errors
3.7 Consideration of breaklines and special points
3.7.1 Neighborhood restrictions
3.7.2 Prescribed tangent planes
3.7.3 Surfaces and lines at special points
4 Parametric patches
4.1 Patches and patch work
4.2 Method overview
4.3 An "G1-continuous polynomial patch
4.3.1 Approximate continuity
4.3.2 Construction of a curve network
4.3.3 Insertion of patches
4.3.4 Insertion of patches and minimizing energy
4.3.5 Additional splitting
4.3.6 Results
5 Subdivision
5.1 The subdivision paradigm
5.2 Method overview
5.3 Subdivision by estimation of local surfaces
5.3.1 The curve case
5.3.2 Surface subdivision with approximating surfaces
5.3.3 Paraboloids vs. general quadrics as local surfaces
5.3.4 Paraboloids vs. second order polynomials as local surfaces
5.3.5 Interpolation and Approximation
5.3.6 Averaging
5.3.7 Roughness detection
5.3.8 Results
6 Examples
6.1 Vertical Wall
6.2 Data set “Elev”
6.3 Breaklines only
6.4 Data set “Albis”
6.5 Bridge
7 Conclusions and Perspectives
7.1 Applications
7.2 Enclaves
7.3 Concluding remarkNuméro de notice : 14314 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Note de thèse : PhD : Vermessung und Geoinformation : Technische Universität Wien : 2002 En ligne : https://repositum.tuwien.at/handle/20.500.12708/390?mode=simple Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62656 Advances in Spatial Data Handling : 10th International Symposium on Spatial Data Handling / Dianne Richardson (2002)
PermalinkAnalyse de données acquises par laser aéroporté pour la reconstruction 3D de scènes urbaines / R. Elkharroubi (2002)
PermalinkAnalyse d'images aériennes haute résolution pour la reconstruction de scènes urbaines / Matthieu Cord in Bulletin [Société Française de Photogrammétrie et Télédétection], n° 166 (Janvier 2002)
PermalinkApport de l'analyse spatiale en géomorphologie : modélisation et approche multiscalaire des risques, Volume 1. Dossier administratif et texte de synthèse / Daniel Delahaye (2002)
PermalinkApports de la télédétection et des SIG à l'étude des inondations de la ville de Saint-Louis du Sénégal / Julien Gaffuri (2002)
PermalinkPermalinkPermalinkPermalinkPermalinkEtude et développement d'un outil d'extraction et d'appariement des éléments caractéristiques du relief à partir de modèles numériques de terrain / E. Colleu (2002)
PermalinkPermalinkPermalinkPermalinkPermalinkProceedings of the GIS Research UK, 10th Annual Conference, GISRUK 2002, 3rd - 5th April, University of Sheffield / Steve Wise (2002)
PermalinkRéalisation d'un système d'information géographique dédié à l'étude des déformations de surface sur la ville de Paris / J.L. Kouame (2002)
PermalinkReconstruction automatique des bâtiments en modèles polyédriques 3-D à partir de données cadastrales vectorisées 2D et d'un couple d'images aériennes à haute résolution / Hassan Jibrini (2002)
PermalinkUse of contour-based DEM for deriving and mapping topographic attributes / H. Mizukoshi in Photogrammetric Engineering & Remote Sensing, PERS, vol 68 n° 1 (January 2002)
PermalinkContrôle terrestre d'un levé par laser à balayage héliporté aux îles Marquises / Q. Gross in XYZ, n° 89 (décembre 2001 - février 2002)
PermalinkPermalink