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On linear transformations of spatial data using the structured total least norm principle / Yaron Felus in Cartography and Geographic Information Science, vol 33 n° 3 (July 2006)  

Public [article]  inCartography and Geographic Information Science > vol 33 n° 3 (July 2006) . - pp 195 - 205 Titre : On linear transformations of spatial data using the structured total least norm principle Type de document : Article/Communication Auteurs : Yaron Felus, Auteur Année de publication : 2006 Article en page(s) : pp 195 - 205 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux [Termes IGN] coordonnées géographiques [Termes IGN] erreur de mesure [Termes IGN] itération [Termes IGN] système de coordonnées [Termes IGN] transformation de coordonnées [Termes IGN] transformation linéaire Résumé : (Auteur) Coordinate transformation is the process of converting spatial data from a source coordinate to a target coordinate system. A set of control points, measured in the two coordinate systems, is used to estimate the transformation parameters. In general, more control points are measured, and the over-determined system is adjusted using the least squares method. However, the standard least squares method assumes that errors exist only in the measurements made at one coordinate system, or at the observation vector (y). This is not the case in many physical systems where errors exist in all the measurements made in both the source coordinate and the target coordinate systems. The Structured Total Least Norm (STLN) method is a relatively new mathematical concept developed to solve estimation problems of so-called Error-In-Variables (EIV) models. The method is specifically suitable for dealing with transformation problems, since it can handle the special structure of the data matrix (A). The STLN method is uniquely used to compute the parameters of common linear coordinate transformations (affine and similarity). A numerical example is presented to demonstrate the superiority of this technique in terms of accuracy and to compare the standard LS method, the generalized LS algorithm, and the STLN approach. Copyright CaGISociety Numéro de notice : A2006-551 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1559/152304006779077273 En ligne : https://doi.org/10.1559/152304006779077273 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28274 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
032-06031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

A practical map labeling algorithm utilizing morphological image processing and force-directed methods / G. Stadler in Cartography and Geographic Information Science, vol 33 n° 3 (July 2006)  

Public [article]  inCartography and Geographic Information Science > vol 33 n° 3 (July 2006) . - pp 207 - 215 Titre : A practical map labeling algorithm utilizing morphological image processing and force-directed methods Type de document : Article/Communication Auteurs : G. Stadler, Auteur ; T. Steiner, Auteur ; J. Beiglböck, Auteur Année de publication : 2006 Article en page(s) : pp 207 - 215 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie numérique [Termes IGN] cartographie numérique [Termes IGN] morphologie mathématique [Termes IGN] placement automatique des écritures [Termes IGN] système d'information géographique Résumé : (Auteur) Automatic placement of text corresponding to graphical objects is an important issue in several applications such as geographical information systems (GIS), cartography, and graph drawing. We focus on realistic data and present a hybrid algorithm for labeling both line and point features. The first step of the method works on the discretized map and uses tools from morphological image processing. It leads to an initial placement of all labels in allowed (i.e., non-overlapping) position. The second step works on the continuous map and uses a force-directed iterative algorithm to improve this initial placement. In a comprehensive study on realistic data sets the strengths of the method (e.g., its flexibility and simple implementation) as well as its limitations (e.g., on dense maps the force-based method is only capable of small adjustments) are discussed. Copyright CaGISociety Numéro de notice : A2006-552 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/152304006779077327 En ligne : https://doi.org/10.1559/152304006779077327 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28275 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
032-06031	RAB	Revue	Centre de documentation	En réserve L003	Disponible