Soetkin Vervust

Ferraris, the Legend

Abstract At the end of the eighteenth century, a large-scale map of the Austrian Netherlands and the Prince-Bishopric of Liège was manufactured, covering more or less the current territory of Belgium. The work for this Carte de Cabinet was carried out by artillerists under the guidance of count Joseph de Ferraris, who was commissioned for the task by the Habsburg government. At the time that the map was designed, no modern legend was included. This paper tries to fill that gap by presenting a legend that was constructed more systematically than any of its predecessors. It is based on the structure of the legend of the Topographic Map of Belgium and the CORINE land cover map, making it an easy-to-use tool for modern researchers. The problems encountered during the development of the legend are described, and the link between the Carte de Cabinet and eighteenth-century French cartography as well as with cartographic manuals is also discussed.

Computation and visualisation of the accuracy of old maps using differential distortion analysis

ABSTRACT The accuracy of old maps can hold interesting historical information, and is therefore studied using distortion analysis methods. These methods start from a set of ground control points that are identified both on the old map and on a modern reference map or globe, and conclude with techniques that compute and visualise distortion. Such techniques have advanced over the years, but leave room for improvement, as the current ones result in approximate values and a coarse spatial resolution. We propose a more elegant and more accurate way to compute distortion of old maps by translating the technique of differential distortion analysis, used in map projection theory, to the setting where an old map and a reference map are directly compared. This enables the application of various useful distortion metrics to the study of old maps, such as the area scale factor, the maximum angular distortion and the Tissot indicatrices. As such a technique is always embedded in a full distortion analysis method we start by putting forward an optimal analysis method for a general-purpose study, which then serves as the foundation for the development of our technique. Thereto, we discuss the structure of distortion analysis methods and the various options available for every step of the process, including the different settings in which the old map can be compared to its modern counterpart, the techniques that can be used to interpolate between both, and the techniques available to compute and visualise the distortion. We conclude by applying our general-purpose method, including the differential distortion analysis technique, to an example map also used in other literature.

Design and use of web lectures to enhance GIS teaching and learning strategies: the students’ opinions

The goal of this research is to design, use and evaluate a set of web lectures, specifically tailored to the needs of students in higher education who follow geographic information system -related courses. Since education in geographic information system includes theoretical concepts and practical experience, both of these teaching strategies will be implemented in the web lectures. The user-centered design approach is used in the design process to increase the acceptance of the web lectures and the motivation to use them: perceived usefulness and ease of use. The results show that the students appreciate the initial set of web lectures, but that they need to be motivated more to use them (especially when theoretical topics are covered). Students still value the “traditional” face-to-face lectures and see the web lectures as an ideal complement.

Count de Ferraris’s Maps of the Austrian Netherlands (1770s): Cassini de Thury’s Geodetic Contribution

ABSTRACT It is generally assumed from something said by the French surveyor Cassini de Thury in his book Relation d’un voyage en Allemagne (1775) that count de Ferraris had incorporated Cassini’s geodetic data into his own maps of the Austrian Netherlands: the manuscript Carte de cabinet (1777) and the Carte marchande (1777). Cassini had carried out a triangulation of the northern part of the Austrian Netherlands during the War of the Austrian Succession (1740–1748), but the extent to which his geodetic data was used by de Ferraris has been the subject of debate. In this article, Cassini’s contribution to de Ferraris’s mapping is reassessed by combining a reinterpretation of the archival record with a metric analysis of de Ferraris’s maps, which shows that de Ferraris used Cassini’s measurements only selectively. This leads to the conclusion that the reason was the limited availability of Cassini’s data and the primarily economic motives for de Ferraris’s use of them.

A study of the local geometric accuracy of Count de Ferraris’s Carte de cabinet (1770s) using differential distortion analysis

ABSTRACT The eighteenth century Carte de cabinet of count de Ferraris is the first large-scale (1:11 520) topographic map of the entire Belgian territory, making it a valuable source of historical information. In the past, a number of studies have tried to assess the geometric accuracy of this map, but they all suffer from restricted technical capabilities for computing and visualizing the distortions, and most of them only focus on a limited number of the 275 map sheets. This paper therefore seeks to provide the first systematic and in-depth investigation of the map’s local geometric accuracy. Recently, two Belgian government agencies georeferenced the Flemish and Walloon part of the Carte de cabinet with a high level of detail, using some 30,000 ground control points to link the old map to the modern topographic map of Belgium. These data sets represent a new and unprecedented potential source of accuracy information. However, the high number of control points and our desire to compute distortions in an exact, local, quantitative and continuous way meant prominent techniques for studying the geometric accuracy of old maps, such as displacement vectors, distortion grids, triangular nets and the popular MapAnalyst software, were unsuited for this task. To meet all our requirements a new technique called Differential Distortion Analysis, which is influenced by the treatment of distortions in map projection theory, was used instead. Its advantages, structure and application to the Carte de cabinet are discussed in detail. The new technique allows calculating and displaying the map’s local angular and surface distortions with a very high spatial resolution. Consequently, it was possible to identify trends in the obtained levels of accuracy and to relate these to historical facts about the Carte de cabinet’s production process. This has resulted in important new insights into the map’s geometric accuracy.

The Mapmakers’ World. A Cultural History of the European World Map. By Marjo T. Nurminen

When I received the book The Mapmakers’ World, which is published in association with the John Nurminen Foundation, I was transported back to July 2013, when I had the pleasure to attend the 25th I...