| Titre : |
Das Relief der Urschweiz von Franz Ludwig Pfyffer (1716-1802) : 3D-Rekonstruktion, Analyse und Interpretation |
| Titre original : |
[Le relief de la Suisse originelle de Franz Ludwig Pfyffer (1716-1802) : reconstruction 3D, analyse et interprétation] |
| Type de document : |
Thèse/HDR |
| Auteurs : |
Jana Niederöst, Auteur |
| Editeur : |
Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH |
| Année de publication : |
2005 |
| Collection : |
IGP Mitteilungen, ISSN 0252-9335 num. 089  |
| Importance : |
211 p. |
| Format : |
21 x 30 cm |
| ISBN/ISSN/EAN : |
978-3-906467-56-6 |
| Note générale : |
Bibliographie |
| Langues : |
Allemand (ger) |
| Descripteur : |
[Vedettes matières IGN] Photogrammétrie
[Termes IGN] analyse comparative
[Termes IGN] carte ancienne
[Termes IGN] carte en relief
[Termes IGN] dix-neuvième siècle
[Termes IGN] méthode de mesure
[Termes IGN] montagne
[Termes IGN] photogrammétrie analogique
[Termes IGN] photogrammétrie numérique
[Termes IGN] précision de localisation
[Termes IGN] précision des mesures
[Termes IGN] reconstruction 3D
[Termes IGN] Suisse
|
| Index. décimale : |
33.00 Photogrammétrie - généralités |
| Résumé : |
(Auteur) The subject of this thesis is one of the most spectacular relief models in history, a large three-dimensional representation of Central Switzerland constructed by Franz Ludwig Pfyffer von Wyher (1716-1802). This masterpiece measures 6.7 m x 3.9 m and is on a scale of about 1: 11500. Pfyffer finished it in 1786 using his own measurements, which he took over a period of 40 years, decades before the first Swiss national triangulation system was established. In the eighteenth century, the relief was a novelty, offering observers a "virtual flight" over a mountainous region that was still unexplored at that time. Contemporary travel writers from all over Europe described their fascination with the model. However, with the appearance of new, more precise maps at the turn of the century, opinions on the topographic quality of the relief started to change: the model was considered merely as a piece of craftwork and was practically forgotten. The manifold possible implications of the relief - not only its topographic, but also its cultural, political, military and aesthetic aspects - have not yet been investigated.
Due to the scarcity of written documentation, this study is based on information derived from Pfyffer's topographic work. First, a precise true-scaled 3D computer model of Pfyffer's Relief was created with the help of photogrammetry and image processing procedures. Next, methods for the quantitative analysis of early cartographic works were developed. These methods were then applied to the computer model of Pfyffer's Relief and related maps of the region, so that new information regarding the process of the relief creation could be extracted. Finally, Pfyffer's achievement is compared with that of his contemporaries.
In order to produce a 3D computer model of Pfyffer's Relief, image-based object reconstruction techniques were applied. From a construction platform fixed at a height of 185 cm above the relief, two sets of images (analogue and digital) were taken, both providing stereo overlap for the whole object. As high accuracy was required and automated image-matching did not bring the expected performance, the phototriangulation and digital elevation model (DEM) measurements were carried out manually on an analytical plotter. The final product of the DEM generation was a regular raster with a grid width of 1 cm and an estimated accuracy of 0.78 mm. The analogue images were scanned at a high resolution, orthorectified and combined to form an orthomosaic. The orthomosaic was then superimposed on the DEM to produce an interactive photorealistic 3D model of the object, which could be used to help reconstruct the physical model in case of damage. The accuracy analysis described below was based on this computer model, as it is much easier and more effective to take measurements on the screen than directly from the complex relief surface.
In the second section of the thesis, fundamental methods for accuracy assessment of old maps and models are described in standard terminology and evaluated. There are only few publications dealing with this topic and those that exist merely analyse old maps: there are no such studies of three-dimensional works. The presented methods are based on a coordinate transformation between identical points in the analysed object and in the modem map. The main focus of this study -beyond the transformation of points - was to determine the metric parameters of a historical map or model. In particular, the 3D affine transformation should be noted. This is the first time that scales, rotation angles and shear values have been isolated and their significance analysed. A new approach for the whole process of accuracy analysis in early cartographic works was developed and implemented in a user-friendly software. The analysis starts with the preparation of input data and the definition of identical points. After the appropriate coordinate transformation, the map or model is georeferenced and a distortion grid is calculated. Finally, a new technique is used to determine the accuracy of polygonal map or relief features.
The third part of the thesis interprets the results achieved by the accuracy analysis. Based on ten of Pfyffer's letters to the famous Swiss scientist Micheli du Crest (1690-1766), Pfyffer's methods for angle, distance and height measurements were reconstructed. It can be concluded that he defined a mesh of large triangles, which he surveyed precisely by triangulation. He oriented his cartographic products using a compass. The orientation angle corresponds with the magnetic north pole, which differed from the geographic one by approximately 14.75 degrees at that time. Thus, the starting date of Pfyffer's surveying can be estimated as about 1747. The planar accuracy of both Pfyffer's Relief and two of his middle-scale maps is roughly 480 m (standard deviation in X- and Y-direction). It is most precise for the area around the city of Lucerne, whereas the geometric quality decreases in more distant regions. Pfyffer's principal instrument for measuring heights was the barometer. He chose Lake Luceme as a zero horizon for his height measurements and estimated its height above sea level with an excellent accuracy of 6 m. Other remarkable achievements include his height measurements in the Bernese Alps. Applying trigonometric measurements he succeeded in precisely determining the heights of the Eiger, MOnch, Jungfrau, Finsteraarhorn, Wetterhorn, Schreckhom and Gross Fieschhorn (height error < 20 m), thus solving one of the great scientific problems in the eighteenth century in Switzerland. Finally, the geodetic achievements of Kyffer were compared with state-of-the-art techniques in Europe at that time. It is shown that his work is comparable with the maps of other regions and countries. His major contribution to progress was systematic height measurement throughout a given area, which marked the start of a new era in cartographic height representation. |
| Numéro de notice : |
15144 |
| Affiliation des auteurs : |
non IGN |
| Thématique : |
IMAGERIE |
| Nature : |
Thèse étrangère |
| En ligne : |
http://dx.doi.org/10.3929/ethz-a-005026536 |
| Format de la ressource électronique : |
URL |
| Permalink : |
https://documentation.ensg.eu/index.php?lvl=notice_display&id=55075 |
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Ajouter le résultat dans votre panier Affiner la recherche Interroger des sources externesDas Relief der Urschweiz von Franz Ludwig Pfyffer (1716-1802) (2005)
Cours de photogrammétrie (1995)
Méthodes et instruments analogiques. B - Correction planimétrique d'une photographie en présence de relief. L'orthophotographie in Bulletin [Société Française de Photogrammétrie et Télédétection], n° 109 (Janvier 1988)
n° D-9 - 1976 - Herstellung topographischer Karten 1:10000 auf photogrammetrischem Weg (Bulletin de Nachrichten aus dem Karten und Vermessungswesen : Sondeveröffentlichung Bundesrepublik Deutschland)
Activité de la commission A de l'OEEPE de 1960 à 1964 (1964)
Betrachtungen und Untersuchungen zur blockweisen Aerotriangulation (1963)
