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Estimation of the positional uncertainty in line simplification in GIS / C.K. Cheung in Cartographic journal (the), vol 41 n° 1 (June 2004)
[article]
Titre : Estimation of the positional uncertainty in line simplification in GIS Type de document : Article/Communication Auteurs : C.K. Cheung, Auteur ; Wei Shi, Auteur Année de publication : 2004 Article en page(s) : pp 37 - 45 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] estimation statistique
[Termes IGN] généralisation cartographique automatisée
[Termes IGN] incertitude géométrique
[Termes IGN] lissage de courbe
[Termes IGN] lissage de données
[Termes IGN] propagation d'incertitude
[Termes IGN] simplification de contour
[Termes IGN] système d'information géographique
[Vedettes matières IGN] GénéralisationRésumé : (Auteur) This paper presents a new model for handling positional uncertainty in the process of line simplification. It considers that positional uncertainty in a simplified line is caused by (a) positional uncertainty in an initial line propagated through the process and (b) a deviation of the simplified line from the initial line. In order to describe the uncertainty in the simplified line, the maximum distance is defined as a measure. This measure is further adopted to determine parameters to a line simplification algorithm. Therefore, this model makes a step forward in the implementation of an uncertainty indicator for the line simplification. As compared existing models, the proposed uncertainty model in this paper is more comprehensive in uncertainty assessment for line simplification Numéro de notice : A2004-279 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1179/000870404225019990 En ligne : https://www.tandfonline.com/doi/abs/10.1179/000870404225019990 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26806
in Cartographic journal (the) > vol 41 n° 1 (June 2004) . - pp 37 - 45[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 030-04011 RAB Revue Centre de documentation En réserve L003 Disponible Smoothing vegetation spectra with wavelets / K.S. Schmidt in International Journal of Remote Sensing IJRS, vol 25 n° 6 (March 2004)
[article]
Titre : Smoothing vegetation spectra with wavelets Type de document : Article/Communication Auteurs : K.S. Schmidt, Auteur ; Andrew K. Skidmore, Auteur Année de publication : 2004 Article en page(s) : pp 1167 - 1184 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] filtrage numérique d'image
[Termes IGN] lissage de données
[Termes IGN] ondelette
[Termes IGN] réflectance spectrale
[Termes IGN] télédétection en hyperfréquenceRésumé : (Auteur) In hyperspectral remote sensing, spectra are increasingly analysed using methods developed for laboratory studies, such as derivative analysis. These techniques require smooth reflectance spectra. Therefore, there is a need for smoothing algorithms that fulfil the requirement of preserving local spectral features while simultaneously removing noise. Noise occurs in variable intensity and over different band widths. Several methods for smoothing a signal exist, including the widely used median and mean filters, the Savitzky-Golay filter applied to laboratory spectra, the cubic spline, and the recently developed transform-based thresholding using the wavelet transform. We compare all these methods using reflectance spectra of the canopy of salt marsh vegetation. The best trade-off between noise reduction and the preservation of spectral features was found to be the wavelet transform, specifically using a translation invariant de-noising based on the non-decimated or stationary wavelet transform. Numéro de notice : A2004-087 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000115085 En ligne : https://doi.org/10.1080/0143116031000115085 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26614
in International Journal of Remote Sensing IJRS > vol 25 n° 6 (March 2004) . - pp 1167 - 1184[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-04061 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Improving tropical forest mapping using multi-date Landsat TM data and pre-classification image smoothing / C. Tottrup in International Journal of Remote Sensing IJRS, vol 25 n° 4 (February 2004)
[article]
Titre : Improving tropical forest mapping using multi-date Landsat TM data and pre-classification image smoothing Type de document : Article/Communication Auteurs : C. Tottrup, Auteur Année de publication : 2004 Article en page(s) : pp 717 - 730 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse diachronique
[Termes IGN] canopée
[Termes IGN] carte de la végétation
[Termes IGN] classification par maximum de vraisemblance
[Termes IGN] écosystème
[Termes IGN] forêt tropicale
[Termes IGN] image Landsat-TM
[Termes IGN] image multitemporelle
[Termes IGN] lissage de donnéesRésumé : (Auteur) The present study explores the possibility of using Landsat imagery for mapping tropical forest types with relevance to forest ecosystem services. The central part in the classification process is the use of multi-date image data and pre-classification image smoothing. The study argues that multi-date imagery contains information on phenological and canopy structural properties and shows how the use of multi-date imagery has a significant impact on classification accuracy. Furthermore, the study shows the value of applying small kernel smoothing filters to reduce in-class spectral variability and enhance between-class spectral separability. Making use of these approaches and a maximum likehood algorithm, six tropical forest types were classified with an overall accuracy of 90.94%, and with individual forest classes mapped with accuracies above 75.19% (user's accuracy) and above 74.17% (producer accuracy). Numéro de notice : A2004-074 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160310001598926 En ligne : https://doi.org/10.1080/01431160310001598926 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26602
in International Journal of Remote Sensing IJRS > vol 25 n° 4 (February 2004) . - pp 717 - 730[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 080-04041 RAB Revue Centre de documentation En réserve L003 Exclu du prêt Modellierung von Oberflächen mit Diskontinuitäten / Andrzej Borkowski (2004)
Titre : Modellierung von Oberflächen mit Diskontinuitäten Titre original : [Modélisation des superficies avec des discontinuités] Type de document : Thèse/HDR Auteurs : Andrzej Borkowski, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 2004 Collection : DGK - C Sous-collection : Dissertationen num. 575 Importance : 91 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-5014-3 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] contour
[Termes IGN] données laser
[Termes IGN] lasergrammétrie
[Termes IGN] lissage de données
[Termes IGN] modèle numérique de terrain
[Termes IGN] semis de points
[Termes IGN] vectorisationIndex. décimale : 35.20 Traitement d'image Résumé : (Auteur) The laser scanning provides very dense information about the surface to be modelled in the form of a irregularly distributed points cloud {x, y, z} c R3. Such dense information makes possible an efficient modelling of characteristic structures of the terrain surface like discontinuities, which are necessary for high-qualitative description of the surface. Simultaneously, the points not belonging to the modelled surface (for example: reflexes from buildings, trees etc.) stand a very important influence on the obtained data. During the modelling process, such data should be effectively filtered from the whole data set.
The laser scanning data can be efficiently elaborated by the use of deformable models of curves and surfaces. These models base on the physical principle of energy-minimizing and are presented as the solution of variational problem. The total energy consists both of internal and external energy. The external energy, depending on a context is generated by the data; in most cases it describes a deviation between the data and a model. The internal energy describes geometrical properties of curves and is characterized by elasticity and viscosity. Both terms are mutually weighted by the local control parameters a and 0. Varying the parameters makes it possible to stretch the curves to a geometrical shapes. The snake-approximation is used for a profiled modelling of surfaces. Due to that, a formulation of external energy was proposed making possible a robust modelling of profiles: during an iterative process, gross errors can be filtered, measuring errors can be smoothed and discontinuities can be preserved. Fitting the snakes-models to the data runs iteratively, however the control parameters depending on the data are being spread.
By generalizing the snakes, the model is introduced by sufficient smoothes, energy-charged pieces of a surface and furthermore described by flakes. The internal energy within the flakes model consists of a membrane and a thin-plate kernel which describes the inclination and curvature properties of the modelled terrain surface. The energy pieces will furthermore be weighted by the local control parameters a and fl. A minimizing of the total flakes energy leads again to the variational problem which had been differently solved. By formulate the Euler equations and their further diskretizing by finite differences, the flakes-model stands for regular data. The previous variational problem will also be solved by the use of so-called Ritz method. The improved flakes model was developed for regular data by using a linear base function. However, for the irregular data the flakes model was modified by the use of a Gaussian function. The modelling of the data by flakes runs iteratively. By using the flakes model for regular data it is possible to reject the gross errors, also to smooth the noise by simultaneous preserving the form of edges.
In many applications the information about spatial location of terrain edges is needed. To present such spatial location description of edges in a vector format based on irregular points cloud {x, y, z} obtained during laser scanning, it was proposed to describe a gross-errors-free data by surface functions and to average the edges as a intersection of two surfaces zi = fi(x, y) ; i = 1, 2. To this purpose, all the data should furthermore be ordered in separate pieces of the surface. This problem can be solved by using the standard methods of image processing. The projection {x(s), y(s)} of edges is found in the xy coordinate plane and the z-coordinates consist of fi (x(s), y(s)). To the intersection of two surfaces relates: f1 (x(s), y(s)) = f2 (x(s), y(s)) = 0. Based on this condition, two approaches of intersection curve identification were developed. The line-tracking algorithm relies on numerical integration of differential equations relative to the particular problem. For the numerical integration there is a starting point needed. Due to that, a seeking-approach was proposed. Opposite to the local algorithm it was presented a global approach using a snakes-method with a proper definition of external energy. Both algorithms make it possible a reliable, high-accurate identification of terrain edges basing on irregular points cloud.
The algorithms and approaches developed in this work have been tested on real data sets obtained by a laser scanning. Furthermore, a qualitative consideration of a modelling has been given. Finally, some hints for user according the steering and operating of the approaches have been presented.Numéro de notice : 13256 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54940 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13256-01 35.20 Livre Centre de documentation Télédétection Disponible The potential of virtual reality technology for analysis of remotely sensed data: a Lidar case study / T. Warner in Geocarto international, vol 18 n° 1 (March - May 2003)
[article]
Titre : The potential of virtual reality technology for analysis of remotely sensed data: a Lidar case study Type de document : Article/Communication Auteurs : T. Warner, Auteur ; M.D. Nellis, Auteur ; T. Brandtberg, Auteur ; J.B. Mc Graw, Auteur ; J.V. Gardner, Auteur Année de publication : 2003 Article en page(s) : pp 25 - 32 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse de données
[Termes IGN] couvert forestier
[Termes IGN] données lidar
[Termes IGN] feuillu
[Termes IGN] forêt tempérée
[Termes IGN] image à haute résolution
[Termes IGN] interactivité
[Termes IGN] interpolation spatiale
[Termes IGN] lissage de données
[Termes IGN] orthophotographie
[Termes IGN] photo-interprétation assistée par ordinateur
[Termes IGN] réalité virtuelle
[Termes IGN] système d'information géographique
[Termes IGN] Virgine Occidentale
[Termes IGN] visualisation 3DRésumé : (Auteur) Although the GIS community has been quick to exploit the advantages of virtual reality (VR) for display and analysis of spatial data, VR does not appear to have been exploited widely for remote sensing data analysis. A case study of high resolution lidar data acquired over a deciduous forest near Morgantown, WV was used to investigate the potential and limitations of current VR software for remote sensing analysis. The functionality within a standard remote sensing software package was found to provide a good overview of interpolated, smoothed lidar data, but was less useful for gridded data that had not been interpolated. With gridded data, it was possible to drape orthophotographs or other images over the lidar data, providing a useful method for investigating relationships between lidar and other data. Alternatively, using a commercial VR package, it was possible to view the original lidar point data, and thus visualize the multiple returns from within the canopy of each tree. The point data were preferable for identification of surfaces within the data cloud, especially the ground surface. For a fully integrated remote sensing VR package, functionality will be needed to link point and interpolated coverages, and also to enhance the interactive selection of data for further statistical analysis, Numéro de notice : A2003-100 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106040308542260 En ligne : https://doi.org/10.1080/10106040308542260 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22396
in Geocarto international > vol 18 n° 1 (March - May 2003) . - pp 25 - 32[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 059-03011 RAB Revue Centre de documentation En réserve L003 Disponible Une grille de lecture pour l'analyse des formes du peuplement en Europe : l'apport d'une méthode de lissage par potentiels / E. Dumas in Revue internationale de géomatique, vol 11 n°3-4 (septembre 2001 - février 2002)PermalinkMachine learning techniques for determining parameters of cartographic generalisation algorithms / Lagrange (Enseigne de Vaisseau) (2000)PermalinkRegionale und globale Gravitationsfeldanalyse hochauflösender Satellitendaten mittels Mehrgitterverfahren / S. Rudolph (2000)PermalinkModelling and Inversion of High Precision Gravity Data / E. Lewi (1997)PermalinkMechanical approach of generalisation / Emmanuel Fritsch (1996)PermalinkDigital image processing / Rafael C. Gonzalez (1993)PermalinkArea-patch generalisation: a competitive approach / Jean-Claude Müller in Cartographic journal (the), vol 29 n° 2 (December 1992)PermalinkAutomatisation de l'extraction du réseau routier sur cartes JOG digitalisées / Marc Pierrot-Deseilligny (1991)PermalinkAn adaptive noise smoothing filter for remotely-sensed images with microphonic noise / S. Cheng in International Journal of Remote Sensing IJRS, vol 10 n° 6 (June 1989)PermalinkEstimation and spectral analysis / J.A.R. Blais (1988)Permalink