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Pour réconcilier les topographes avec les nombres complexes / Emmanuel Clédat in XYZ, n° 148 (septembre - novembre 2016)
Titre : Pour réconcilier les topographes avec les nombres complexes Type de document : Article/Communication Auteurs : Emmanuel Clédat , Auteur
Année de publication : 2016 Article en page(s) : pp 47 - 53 Note générale : bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Topographie
[Termes IGN] nombre complexe
[Termes IGN] polygonation
[Termes IGN] relèvement
[Termes IGN] transformation de HelmertRésumé : (auteur) Les nombres complexes tirent leurs origines du milieu du 16e siècle, où ils auraient été introduits pour la première fois par Jérôme Cardon pour permettre la résolution d'équations polynomiales de degrés supérieur à 2. Ils sont nés en tant qu'artifices mathématiques ou "monstres du monde des idées", c'est ainsi que Gottfried Wilhelm Von Leibniz les appelait en référant à l'allégorie de la caverne de Platon. L'Histoire des mathématiques prend parfois des chemins détournés dans ses découvertes : ces nombres complexes sont passés du monde des idées au monde réel en s'incarnant dans tous les problèmes géométriques chers aux topographes. Numéro de notice : A2016-733 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82265
in XYZ > n° 148 (septembre - novembre 2016) . - pp 47 - 53[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 112-2016031 RAB Revue Centre de documentation En réserve 3L Disponible Documents numériques
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Pour réconcilier les topographes - pdf éditeurAdobe Acrobat PDF
Titre : Accuracy evaluation for automated optical indoor positioning using a camera phone Type de document : Article/Communication Auteurs : V. Händler, Auteur ; V. Willert, Auteur Année de publication : 2012 Article en page(s) : pp 114 - 122 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] analyse comparative
[Termes IGN] classification
[Termes IGN] estimation de précision
[Termes IGN] GNSS assisté pour la navigation
[Termes IGN] image terrestre
[Termes IGN] porte
[Termes IGN] positionnement en intérieur
[Termes IGN] relèvement
[Termes IGN] système optique
[Termes IGN] téléphone intelligentRésumé : (Auteur) In this paper, we focus on the accuracy of optical indoor positioning and the design of an automated and mobile positioning system based on pictures taken by a cell phone camera. We restrict ourselves to automated relative pose estimation given only one image including the projection of an object with four reference points with known image and world coordinates. To infer the relative pose from the image coordinates of the reference points, we first have to detect and classify an object, afterwards localize the image coordinates, and finally apply spatial resection. We show, that if an object is correctly classified, then the quality of the positioning heavily depends on the accuracy of the localization of the image coordinates and on the choice of the spatial resection algorithm. To this end, we compare three different spatial resection algorithms and present two combinations of object classification and image coordinate localization techniques using doors as known objects. Statistical evaluations are provided to judge the different classification methods in terms of robustness and to present the accuracy of the image coordinate localization techniques. Numéro de notice : A2012-267 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31713
in ZFV, Zeitschrift für Geodäsie, Geoinformation und Landmanagement > vol 137 n° 2 (01/03/2012) . - pp 114 - 122[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 199-2012021 RSREV Revue Centre de documentation Revues en salle Disponible Estimating sea floor dynamics in the southern North Sea to improve bathymetric survey planning / L. Dorst (2009)
Titre : Estimating sea floor dynamics in the southern North Sea to improve bathymetric survey planning Type de document : Monographie Auteurs : L. Dorst, Auteur Editeur : Delft : Netherlands Geodetic Commission NGC Année de publication : 2009 Collection : Netherlands Geodetic Commission Publications on Geodesy, ISSN 0165-1706 num. 69 Importance : 220 p. Format : 17 x 24 cm ISBN/ISSN/EAN : 978-90-6132-311-2 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bathymétrie
[Termes IGN] bathymétrie
[Termes IGN] covariance
[Termes IGN] déformation de la croute terrestre
[Termes IGN] fond marin
[Termes IGN] géodynamique
[Termes IGN] géostatistique
[Termes IGN] interpolation
[Termes IGN] krigeage
[Termes IGN] marée océanique
[Termes IGN] morphogenèse
[Termes IGN] nivellement indirect
[Termes IGN] Nord, mer du
[Termes IGN] océanographie dynamique
[Termes IGN] port
[Termes IGN] relèvement
[Termes IGN] Rotterdam (Pays-Bas)
[Termes IGN] sable
[Termes IGN] vagueRésumé : (Auteur) Safe nautical charts require a carefully designed bathymetric survey policy, especially in shallow sandy seas that potentially have dynamic sea floor patterns. Bathymetric resurveying at sea is a costly process with limited resources, though. A pattern on the sea floor known as tidal sand waves is clearly present in bathymetric surveys, endangering navigation in the Southern North Sea because of the potential dynamics of this pattern. An important factor in an efficient resurvey policy is the type and size of sea floor dynamics. The uncertainties of measurement and interpolation associated with the depth values enable the statistical processing of a time series of surveys, using deformation analysis. Currently, there is no procedure available that satisfies the Royal Netherlands Navy requirements. Therefore, a deformation analysis procedure is designed, implemented and tested in such a way that the procedure works on bathymetric data and satisfies the Royal Netherlands Navy requirements. Also, it is necessary to develop a procedure that translates the results into changes of the resurvey policy, taking into account their confidence intervals.
To describe the sea floor statistically, we assume the sea floor to consist of a spatial trend function (or characterization) and a residual function (or dispersion). Such a description is called a representation. The covariances between positions are expressed in a covariance function, based on the residual function. The covariance function is used by Kriging, an interpolation procedure that propagates the variances and covariances of the data points to variances of the interpolated values. This approach is used widely for spatial analyses, like the interpolation of a bathymetric data set.
The method that we propose uses Kriging to produce a time series of grids of depth values and their variances. Subsequently, it uses deformation analysis, a statistical procedure based on testing theory. Our application of deformation analysis is particularly aimed at the detection of dynamics in areas with tidal sand waves, resulting in parameter estimates for the sea floor dynamics, and their uncertainty. We apply the method to sea floor representations both with and without a sand wave pattern. A test scenario is set up, consisting of a survey of an existing area in the Southern North Sea, for which dynamics are simulated. The results show that the proposed method detects different types of sea floor dynamics well, leading to satisfactory estimates of the corresponding parameters.
We show results for the anchorage area Maas West near the Port of Rotterdam, the Netherlands first. The area is divided into 18 sub-areas. The results show that a sand wave pattern is detected for most of the sub-areas, and a shore-ward migration is detected for a majority of them. The estimated migration rates of the sand waves are up to 7.5 m/yr, with a 95% confidence interval that depends on the regularity of the pattern. The results are in confirmation with previously observed migration rates for the Southern North Sea, and with an idealized process-based model.
Thereafter, we analyze several other areas for which a time series of surveys is available in the bathymetric, archives of the Netherlands Hydrographic Service, to study the spatial variations in sea floor dynamics. We present results for several sand wave areas and a single flat area. In some of those areas, dredging takes place, to guarantee minimum depths. The results indicate sand wave migration in areas close to the coast, and bed level changes of the order of decimeters. The dominant wavelength of the sand waves varies. We compare our results to literature of the same sand wave areas, in which we find similar migration rates, and different wavelengths.
By formulating four indicators, recommendations are made for the resurvey policy on the Belgian and Netherlands Continental Shelf. These indicators follow from the estimates for sea floor dynamics. We present a concept for the shallowest likely depth surface, on which we base two of the indicators. The other two indicators act as a warning: they quantify the potentially missed dynamics, which makes the procedure more robust in case of complicated morphology. We show clear differences in recommended resurvey frequency between the five analyzed regions.
We conclude that the designed method is able to use a time series of bathy-metric surveys for the estimation of sea floor dynamics in a satisfactory way. Those dynamics may be present on the scale of the sea floor, it may be a local effect, or it may be due to a tidal sand wave pattern. Also, the results are successfully reduced to a set of four indicators, used to improve a resurvey policy. Based on these conclusions, we formulate recommendations on the extrapolation of the results in space and time, on potential adaptations to the designed procedure, and on implementation of the procedure.Note de contenu : Preface
1 Introduction
1.1 Nautical charting
1.2 Survey plan design
1.3 Detection of sea floor dynamics
1.4 Tidal sand waves
1.5 The uncertainty of depth measurements
1.6 Problem formulation
1.7 Research question and subquestions
1.8 Research strategy and outline
2 Bathymetric applications of Geostatistics
2.1 Introduction
2.2 Depth as a trend and its residuals
2.3 Covariance functions
2.4 Kriging
2.5 Conclusion
3 Estimating sea floor dynamics
3.1 Introduction
3.2 The method for the estimation of sea floor dynamics
3.3 Specification of a test scenario
3.4 Analysis results of a dynamic sea floor
3.5 Discussion
3.6 Conclusion
3.A Error characteristics
3.B Transformation of the sand wave parameters
3.C The application of statistical estimation and testing
4 The analysis of migrating tidal sand waves
4.1 Introduction
4.2 The application of deformation analysis
4.3 Results of the deformation analysis
4.4 Discussion of results
4.5 Conclusion
4.A Overview of used surveys
4.B Quantification of measurement errors
4.B.1 Covariance function of the error
4.B.2 Variances of the SEES surveys
4.B.3 Variances of the MBES survey
5 Spatial variations in sea floor dynamics
5.1 Introduction
5.2 Deformation analysis
5.3 The Selected Track region: little dynamics
5.4 The Noordhinder region: comparison with other methods
5.5 The region West of IJmuiden: sand wave migration
5.6 The region North of Terschelling: a flat sea floor
5.7 Discussion
5.8 Conclusion
5.A Overview of used surveys
6 Application to the resurvey policy
6.1 Introduction
6.2 Background: Hydrographic practice
6.3 Method: indicators of sea floor dynamicsNuméro de notice : 15495 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62737 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 15495-01 32.10 Livre Centre de documentation Topographie Disponible
Titre : Evaluation of the Newton-Raphson method for three-point resection in photogrammetry Type de document : Article/Communication Auteurs : S.M. Easa, Auteur Année de publication : 2007 Article en page(s) : pp 33 - 42 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] méthode itérative de Newton-Raphson
[Termes IGN] relèvement
[Termes IGN] relèvement photogrammétriqueRésumé : (Auteur) Three-point resection in photogrammetry (based on measured distances between three object points and the corresponding image coordinates) has been a viable approach because it does not require data on the object coordinates. Many iterative and closed-form solutions of the problem have been developed. The problem may have up to four solutions for the distances between the exposure station and the objects. Due to the complexity of the closed-form solutions, a simple method involving Newton-Raphson (N-R) search has recently been suggested for determining the unique (correct) solution for the Grunert's quartic polynomial. The N-R method, however, may not converge to the unique solution. This paper first describes the geometry of the three-point resection and the difficulties with the N-R method. A new Excel-based method that identifies all four solutions of the quartic polynomial is then presented. The method does not require initial estimates of the roots. Situations in which the N-R method is useful are highlighted. Application examples are used to illustrate the issues and concepts addressed. The proposed method, which provides insights into space resection, should be of interest to both researchers and educators. Copyright SaLIS Numéro de notice : A2007-211 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83654
in SaLIS Surveying and land information science > vol 67 n° 1 (March 2007) . - pp 33 - 42[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 121-07011 RAB Revue Centre de documentation En réserve 3L Disponible
Titre : Solving algebraic computational problems in geodesy and geoinformatics : The answer to modern challenges Type de document : Monographie Auteurs : Joseph L. Awange, Auteur ; Erik W. Grafarend, Auteur Editeur : Berlin, Heidelberg, Vienne, New York, ... : Springer Année de publication : 2005 Importance : 334 p. Format : 16 x 24 cm ISBN/ISSN/EAN : 978-3-540-23425-8 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] anneau
[Termes IGN] coordonnées cartésiennes géocentriques
[Termes IGN] coordonnées ellipsoïdales
[Termes IGN] géomètrie algorithmique
[Termes IGN] modèle de Gauss-Markov
[Termes IGN] Ploynôme
[Termes IGN] positionnement par GPS
[Termes IGN] relèvement
[Termes IGN] transformation de coordonnées
[Termes IGN] transformation géométrique
[Termes IGN] valeur aberranteRésumé : (Editeur) The book presents modern and efficient methods for solving Geodetic and Geoinformatics algebraic problems using computer algebra techniques of Ring, polynomials, Groebner basis, resultants, Gauss-Jacobi combinatorial and Procrustes algorithms. Although these problems are traditionally solved by approximate methods, this book presents alternative algebraic techniques based on computer algebra tools. This new approach meets such modern challenges as resection by laser techniques, solution of orientation in robotics, transformation and bundle block adjustment in geoinformatics, densification of engineering networks, analytical solution for GPS-meteorology and many other problems. For mathematicians the book provides some practical examples of abstract algebra application and multidimensional scaling. Note de contenu : 1. Introduction
2. Basics of Ring Theory
3. Basics of Polynominal Theory
4. Groebner Basis
5. Polynomial resultants
6. Gauss-Jacobi Combinatorial algorithm
7. Local versus Global Positioning Systems
8. Partial procrustes and the orientation problem
9. Positioning by ranging
10. From geocentric cartesian to ellipsoidal coordinates
11. Positioning by resection method
12. Positioning by intersection method
13. GPS Meteorology in environmental monitoring
14. Algebraic diagnosis of outliers
15. Transformation problem : procustes algorithm 2
16. Computer algebra systems.Numéro de notice : 12687 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Monographie Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54752 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 12687-01 30.04 Livre Centre de documentation En réserve 2S (M-103) Disponible PermalinkPermalinkPermalinkPermalinkPermalinkPermalinkPermalinkPermalinkPermalinkPermalink
