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IMAGE ANALYSIS FOR THE HISTORY OF CARTOGRAPHY: 
DRAWING CONCLUSIONS FROM THE EVALUATION OF PFYFFER'S RELIEF 
Jana Niederóst 
Institute of Geodesy and Photogrammetry, Swiss Federal Institute of Technology Zurich, 
ETH-Hônggerberg, CH-8093 Zurich, Switzerland, jana@geod.baug.ethz.ch 
TS-PS WG V/4 Image Analysis and Spatial Information Systems for Application in Cultural Heritage 
KEYWORDS: cultural heritage, history of cartography, digital recording, accuracy analysis, surveying reconstruction 
ABSTRACT: 
Digital photogrammetry offers effective and accurate procedures for the preservation and inventory of cultural heritage. In case of 
two- and three-dimensional products of early mapmaking the application of these methods goes far beyond documentation and 
visualization: it primarily aims at the derivation of new information. This paper reports on conclusions which can be drawn from the 
quantitative evaluation of one of the most spectacular relief models in history, the relief of Franz Ludwig Pfyffer constructed 
between 1750 and 1786. At first, the techniques and results of image-based reconstruction and accuracy analysis of this masterpiece 
are briefly summarized. Due to the lack of written documentation concerning the relief and its constructor, the virtual Pfyffer's Relief 
and the products of image processing represent a great potential for research in the history of cartography. Thus, the main focus of 
the paper is the reconstruction of Pfyffer's surveying procedures and the interpretation of the reached accuracy in context of 
European mapmaking of that period. The work leads to a new knowledge about the cartographic, spatiotemporal but also social and 
political aspects of the relief creation. As opposed to the previous assumptions it can be concluded that Pfyffer performed systematic 
and repetitive triangulation and height measurements. His procedures, instruments and results correspond with the scientific status 
quo in the last quarter of the 18th century, whereas his area-wide height survey was a pioneering achievement at that time. 
1. INTRODUCTION 
Old maps and three-dimensional relief models are an important 
part of our cultural heritage. They bear witness of the technical 
development, social, cultural and politic circumstances as well 
as of the comprehension of space and landscape at the time they 
had been created. As such they are precious material, pieces of 
art that help us to understand our history, territorial dynamics 
and progress of scientific knowledge. The digital recording of 
two- and three-dimensional historical cartography enables its 
preservation for the next generations; however, primarily it 
should serve for the derivation of new information. Due to the 
lack of primary written sources this "added value" - gained 
through the recovering of the metrical content of old 
topographic works by means of statistical and image processing 
procedures - is very worthwhile for the historical research. This 
paper shows how the results of accuracy analyses and 
visualization can be interpreted and hence, which new 
conclusions can be drawn concerning the early mapmaking at 
that period. 
The object of the research is one of the most spectacular relief 
models in history, a large bird's eye view of mountainous 
Central Switzerland constructed by the lieutenant general Franz 
Ludwig Ptyffer (1716-1802) between 1750 and 1786. The 
topographic base of this 6.6 x 3.9 m big masterpiece at a scale 
of about 1:11'500 are the own measurements of Pfyffer, 
performed decades before the first Swiss national triangulation 
was established. The visual verification shows that the relief 
was a significant improvement of existing maps at that time 
(Fig. 1) and it also served as a basis for several printed works 
issued at the end of 18th century. However, because of the very 
Spare written documentation and the relief complexity, neither 
its formation nor its geometric characteristics have been 
investigated up till now. Within the scope of an 
interdisciplinary project supported by the Swiss National 
Science Foundation and the local cultural authorities, the 
methods for the quantitative evaluation of old maps and relief 
models are to be developed. The application of these 
procedures to the Pfyffer's Relief (or more precisely, to its 
virtual computer model) and related maps of the region should 
answer the questions of historians concerning the creation, 
accuracy and historical context of the relief. The indirect 
analysis of Pfyffer's topographic work as the only possible way 
of exploring this chapter of Swiss cartography should complete 
the following three tasks: 
e 3D reconstruction of the relief for the documentation of 
the cultural heritage and for the numerical evaluation of 
geometric features of the original, 
e Accuracy analysis of the relief and related old maps; 
interpretation of the results in the context of European 
mapmaking at that period, 
e Investigation of  Pfyffers surveying and model 
constructing procedures; comparison with contemporary 
and present methods. 
  
  
Fig. 1: The depiction of Central Switzerland (a) in the principal 
map of the region over the whole 18th century (Nova Helvetiae 
Tabula Geographica, J. J. Scheuchzer, 1712), (b) in the 
georeferenced Pfyffer's Relief overlaid with the current lake 
contours (blue lines).