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Stochastisch-geometrische Beschreibung, Filterung und Präsentation des Reliefs / Andrzej Borkowski (1994)
Titre : Stochastisch-geometrische Beschreibung, Filterung und Präsentation des Reliefs Titre original : [Description géométrique aléatoire, filtrage et présentation du relief] Type de document : Thèse/HDR Auteurs : Andrzej Borkowski, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1994 Collection : DGK - C Sous-collection : Dissertationen num. 431 Importance : 85 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 3-7696-9474-4 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] discrétisation
[Termes IGN] entropie
[Termes IGN] filtrage linéaire
[Termes IGN] modèle numérique de terrain
[Termes IGN] représentation discrèteIndex. décimale : 33.30 Photogrammétrie numérique Résumé : (Auteur) This Doctoral thesis covers two main items: the linear relief filtering with restrictions and the discretization of relief without information loss. The modelling of the relief, which is assumed to be a realization of a two-dimensional normal, homogeneous, and bandlimited stochastic process, is based on the theory of stochastic processes. The adequacy of the model choice and its assumptions has been verified using some natural reliefs of the Earth's surface.
Concerning linear filtering the following quantity and quality restrictions were used: preservation of relief shape, of volume, of terrain inclination and finally, the reduction of relative extremums according to Toepfer's choice rule are expressed in stochastic process terminology. The above conditions are realized by the two-dimensional, non-recursive, digital linear filtering (e.g. for generalization purposes, for relief smoothing using digital data). In order to estimate the required parameters the complete knowledge of second order process quantities (autocovariance function or spectral density) is necessary. Numerical experiments with different relief types stored in digital terrain models (DTM) confirmed the possibility of practical realization of linear filtering with restrictions.
The conventional sampling theorem concerning bandlimited random signals is based on the discretization of the abscissa. In opposite to that, the contour line representation of the relief corresponds to a discretization on the ordinate. Sampling rules according to the ordinate, consistent with the original sampling theorem, are given for both one-dimensional and two-dimensional continuous stochastic processes and additionally for discrete signals (time series). Vertical and horizontal intervals of discretization relate to each other by the correlation coefficients of neighboured signal values for discrete signals or by the second order moment of terrain inclination for continuous processes. An estimation approach for optimum grid cell size of DTM interpolated from topographic maps is proposed. This grid ensures a complete as well as a non-redundant data capture from contour line information. The approach is based on the relation between vertical and horizontal intervals of discretization. The necessary parameter i.e. the variance of terrain inclination is estimated using measured lengths of contour lines at different height levels. The consistence of the discretization rules has been confirmed by numerical experiments.Numéro de notice : 28057 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63404 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28057-01 33.30 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible 28057-02 33.30 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible
Titre : Struktur- und Funktionswandel im amtlichen Vermessungswesen Titre original : [Évolution des fonctions et des structures dans l'organisation officielle de la géodésie-topographie] Type de document : Thèse/HDR Auteurs : Viktor Eisele, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1994 Collection : DGK - C Sous-collection : Dissertationen num. 428 Importance : 154 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9471-0 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Cartographie étrangère
[Termes IGN] activité géodésique
[Termes IGN] Bade-Wurtemberg (Allemagne)
[Termes IGN] cartographie étrangère
[Termes IGN] dix-neuvième siècle
[Termes IGN] histoire de la cartographie
[Termes IGN] vingt-et-unième siècle
[Termes IGN] vingtième siècleNuméro de notice : 28060 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Thèse étrangère DOI : sans En ligne : https://www.ifp.uni-stuttgart.de/dokumente/Dissertationen/C428-Eisele.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63407 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28060-01 39.40 Livre Centre de documentation Cartographie Disponible 28060-02 39.40 Livre Centre de documentation Cartographie Disponible Universaltheodolit und CCD-Kamera, ein unpersönliches Meßsystem für astronomisch-geodätische Beobachtungen / W. Schirmer (1994)
Titre : Universaltheodolit und CCD-Kamera, ein unpersönliches Meßsystem für astronomisch-geodätische Beobachtungen Titre original : [Théodolite universel et chambre DTC : un système de mesures à distance pour des observations astro-géodésiques] Type de document : Thèse/HDR Auteurs : W. Schirmer, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1994 Collection : DGK - C Sous-collection : Dissertationen num. 427 Importance : 93 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9470-3 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie
[Termes IGN] chambre DTC
[Termes IGN] étalonnage d'instrument
[Termes IGN] étalonnage de chambre métrique
[Termes IGN] instrumentation Kern
[Termes IGN] théodolite électronique
[Termes IGN] vidéothéodoliteIndex. décimale : 30.03 Instruments de géodésie Résumé : (Auteur) This doctoral thesis shows how to use an universal theodolite kern DKM 3-A and a ccd-camera as an impersonal measuring system for astro-geodetic observations. The measuring system is established here, calibrated and proved by simultaneous determination of latitude, longitude and azimuth.
The first chapter introduces the subject with the given task and a glance at the relevant history. Next is an overview of the measuring system. Chapter 2 deals with the combination and calibration of universal theodolite and ccd-camera, starting with the basic functioning principle of charge coupled devices (ccd) and their use as image aquisitors in video cameras. There are several special items which have to be considered if ccd-sensors are applied to measurements in videometry. The imaging system used here is then described.
The third chapter covers the theory of eccentric pointings, that means pointings not centered at the intersection point of the crosshairs of a (video) theodolite. Some existing considerations are reported and uniformly represented. Correct formulae for the transformation of eccentric observations in^o directions are derived in two different ways. They are compared to existing approximations. Some recommendations of how to observe with video theodolites follow from a consideration of pointings in different positions.
Chapter 4 considers the special requirements for astro-geodetic observations with a video theodolite. Because stars are moving targets there are some considerations to be made concerning telescope properties, the video imaging techniques and time measurement. Next there is a point determination algorithm selected from existing methods. Its resolution and accuracy are adapted to the used instruments. Lastly, remarks about observation practice and calculation of the results are given.
Finally, chapter 5 shows the results, which can be summarized by the characteristic accuracy for simul-taneous star observations: the standard deviations for latitude, longitude and azimuth are better than half an arc second. The differences of the values known from other determinations for the used observation point are also as accurate. Only for longitude (time) is there a systematic difference of 0.3 time seconds, however this can be calibrated.
The concluding chapter 6 gives a summary and a short outlook for possible future ideas.Numéro de notice : 28061 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63408 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28061-01 30.03 Livre Centre de documentation En réserve M-103 Disponible 28061-02 30.03 Livre Centre de documentation En réserve M-103 Disponible Untersuchungen zur Leistungsfähigkeit elektronischer Druckaufnehmer für präzise barometrische Höhenmessungen / A. Sudau (1994)
Titre : Untersuchungen zur Leistungsfähigkeit elektronischer Druckaufnehmer für präzise barometrische Höhenmessungen Titre original : [Etude de faisabilité d'un capteur électronique de pression pour un nivellement barométrique précis] Type de document : Thèse/HDR Auteurs : A. Sudau, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1994 Collection : DGK - C Sous-collection : Dissertationen num. 434 Importance : 142 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9477-2 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Nivellement
[Termes IGN] instrument de nivellement
[Termes IGN] nivellement barométriqueIndex. décimale : 30.03 Instruments de géodésie Résumé : (Auteur) Electronic pressure sensors are available since about a decade. The first results of a motorized barometric levelling with low cost sensors showed that these sensors already have the accuracy of Thommen-barome-ters. Therefore it can be expected that precise barometric levelling within an accuracy of 1-2 dm is possible by using precise pressure sensors. This requires a precision of the pressure measurements of some 1/1000 hPa.
At first an overview is given of the most important principles of electronic pressure measurement. Beside that the capacity of different sensor types is investigated. Based on the analysis of this data the Digiquartz-Transmitter PAROSCIENTIFIC 1015A was chosen for this researchwork.
In a lot of test measurements the sensor-specifications given by the producer could be verified and the influences on barometric levelling caused by the instrument are analysed. The results of the tests show that the PAROSCIENTIFIC-Transmitter is qualified for precise barometric levellings.
The use of precise instruments requires an analysis and development of the models for the determination of barometric levelling used until now. Different models of computing and adjusting barometric heights are discussed. Depending on the model used the barometric heights are handled as correlated observations. Without any more information the precision of the barometric heights can be estimated by using observa-tion differences. The consideration of geometric leveled heights offers the possibility to determine the trueness of the barometric heights.
Finally barometric measurements are executed for testing the PAROSCIENTIFIC-Transmitters and the developed theoretical models in practice. The results of these experiments show that it is possible to achieve an accuracy of the barometric heights of 0.07-0.16 m. Such accuracies cannot be achieved with conventional barometers because they are not able to detect a lot of important systematic influences on the measurements. This is only possible using a precise sensor in combination with the developed models.Numéro de notice : 28055 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63402 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28055-01 30.03 Livre Centre de documentation En réserve M-103 Disponible 28055-02 30.03 Livre Centre de documentation En réserve M-103 Disponible Zur Bestimmung des Erdschwerefeldes unter Verwendung des Maximum-Entropie-Prinzips / Rüdiger Lehmann (1994)
Titre : Zur Bestimmung des Erdschwerefeldes unter Verwendung des Maximum-Entropie-Prinzips Titre original : [Sur la détermination du champ de pesanteur terrestre en utilisant le principe d'entropie maximale] Type de document : Thèse/HDR Auteurs : Rüdiger Lehmann, Auteur Editeur : Munich : Bayerische Akademie der Wissenschaften Année de publication : 1994 Collection : DGK - C Sous-collection : Dissertationen num. 425 Importance : 103 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-7696-9468-0 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Géodésie physique
[Termes IGN] Baltique, mer
[Termes IGN] champ de pesanteur local
[Termes IGN] distribution de Gauss
[Termes IGN] entropie
[Termes IGN] harmonique sphérique
[Termes IGN] levé gravimétrique
[Termes IGN] méthode de Monte-Carlo
[Termes IGN] problème inverse
[Termes IGN] système non linéaireIndex. décimale : 30.40 Géodésie physique Résumé : (Auteur) The thesis deals with the problem of determining the outer gravity field of the Earth based on a finite number of data affected by measurement errors. It is described as a discrete inverse problem in an informational framework suggested by Tarantola and Valette (1982). Based on a conjunction operation for different states of information, a very general solution scheme for such problems is provided. For the first time we give a complete axiomatic foundation of this operation.
The mainstay of this work is the application of the solution scheme to the problem of modelling the disturbing potential in the outer space of the Earth. It is necessary to extend the scheme to account for unknown variance components, namely the squares of the unavoidable modellization errors. The result is not immediately a spatial potential function, but a state of information for the value of the disturbing potential at any point in the outer space, being the result of the conjunction of the states of information available. The solution scheme does not suggest a certain type of model for the representation of the potential, e.g. spherical harmonics could be used. Here the method of point masses in free (optimized) positions serves as an illustrating example.
For the definition of the probability distributions used we exclusively rely on the maximum entropy principle. This gives the least informative state of information consistent with given constraints. In this context the problem of constructing probability distributions for mass anomalies inside the Earth subject to spectral constraints for the outer gravity field is treated. The solution is presented for point mass anomalies and a number of practically occuring spectral constraints, both on a sphere as well as in a tangential plane.
In general, the probability distributions finally obtained for the representation of the state of information on the disturbing potential cannot be expressed analytically, because a multidimensional integral is not analytically tractable. However, two special cases exist, where an analytical solution is possible. Then we obtain either a t-distribution or a normal distribution for the disturbing potential value, both very well suited for estimation. In the remaining cases the resulting probability distributions can only be described by means of characteristic parameters. First of all, we investigate both the expectation as well as the mode (maximum likelihood point). Again, as the multidimensional integrals involved have no analytical solution, both can in general not be computed directly. Without numerical integration only the joint mode over the space of model parameters, modellization error squares, and the disturbing potential can be computed. This is accomplished by solving a nonlinear equation system.
If any, only the method of Monte Carlo integration is powerful enough to provide numerical approximates for the multidimensional integrals to be evaluated. The crucial point here is the proper choice of the pseudorandom distributions. For truely large dimension numbers even expensively determined pseudorandom distributions fall short. In a simple synthetic simulation study we compute marginal probability distributions for model parameters, for the modellization errors as well as for the disturbing potential by means of the Monte Carlo integration technique. In a larger scale simulation example, modelled close to the real behaviour of the gravity field in the Gulf of Bothnia, we try to assess biases of the maximum likelihood estimate. The Monte Carlo integration as well as the average second order remainder assessment do not agree well. Here the only conclusion to be drawn is: The biases do not form the largest constituent of the posterior errors in the results.
Finally we compute a local gravity field based on real data on the Gulf of Bothnia. We process more than 11000 gravimetric and more than 900 altimetric data. The results are two maximum likelihood solutions for up to 750 point masses in free positions. The first is based exclusively on the gravimetric data. The predicted geoid fits the altimetrically surveyed sea surface within 11 cm, that is not much more than the actual error of the altimetry. The second solution also includes the altimetry. Unlike the original method of point masses in free positions, we are now able to handle problems with different types of data, different data accuracies, as well as inhomogeneous spatial data coverage. This indicates the power of the suggested approach.Numéro de notice : 28063 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=63410 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 28063-01 30.40 Livre Centre de documentation Géodésie Disponible 28063-02 30.40 Livre Centre de documentation Géodésie Disponible Zur Verfahrensdisposition bei der Digitalen Orthoprojektion / W. Mayr (1994)PermalinkAnalyse der Form und Lage von Objekten im Raum / E. Drixler (1993)PermalinkBildorientierung und Objektrekonstruktion mit Punkten, Linien und Flächen / Günter Strunz (1993)PermalinkDas allgemeine Trilaterationsproblem und seine inkongruenten Lösungen / G. Albrecht (1993)PermalinkEin quasi-geostrophisches Strömungsmodell zur Auswertung von Satelliten-Altimeterdaten / N. Arent (1993)PermalinkExemplarischer Aufbau eines Planungsinformationssystems für die ländliche Neuordnung / A. Stark (1993)PermalinkGPS-Verfahren für den Nahbereich mit kurzen Beobachtungszeiten in Vermessung und Ortung / K. Sauermann (1993)PermalinkInverse und schlecht gestellte Probleme bei der digitalen photogrammetrischen Objekt-Rekonstruktion / Y.J. Zheng (1993)PermalinkKonfigurationsoptimierung ausgleichender Funktionen mit Hilfe von Kriteriummatrizen / V. Stegelmann (1993)PermalinkPermalink