The 4th International Laboratory for the History of Science
Art, Science and Techniques of Drafting in the Renaissance

Protocol Saturday, 26 May 2001
(by Raz. D.Chen-Morris)

Perspective and Map Making
Perespective and Map Making: Topography, Urban Views and Instruments

The fact that Alberti applied the same instrument to measure a sculpture and to draw a map of Rome, raises the question what was the relationship, if any, between pictorial perspective and cartography? Another related question is: in what ways did Ptolemy´s third projection mold both the technique of pictorial perspective and map projection through the 15^th and 16^th centuries?
Professor Woodward contended that map projection is a complex notion that depended upon the number of points of view (i.e., centers of projection, ranging from one ton infinite) and the manner in which they imply, or do not imply, the sphericity of the earth. Therefore, there is no direct link between pictorial perspective and map projection. Further, Ptolemy´S third projection did not win the field of cartography until the early 16^th century. Finally, since world maps, unlike sea charts, were not supposed to have practical value, the application of Ptolemy´s third projection has had a symbolic value, and should be understood as such.

On the same track, Angelo Cattaneo attempted to turn Edgerton´s thesis upside down and to contend that artificial perspective shaped the way late fifteenth century cartographers and painters understood Ptolemy´s Geographia in general and his third projection in particular. This thus implies a sort of symbolic form, or paradigm with perspective as it's governing principle.

The second part of the day was dedicated to urban views and surveying instruments. Lucia Nuti emphasized the dislike of Italian artists towards optical instruments. Taste changed in the second half of the 16^th century when Vasari drew a topographical view of Florence with the help of a compass.
Following Nuti´s paper Philipo Camerota presented an instrument for curvilinear perspective (or panoramic) drawings used for urban views as well as for military purposes.

Questions and Ideas for Discussion:

Can one really dismiss the relevance of Ptolemy´s theories for cartographers? These theories were available since the early 15^th century. How else might have humanists have read and understood Ptolemy`s text? What other applications did humanists have for such a highly complex text of practical mathematics (is Ptolemy`s Geographia really a practical mathematics?)

What needs did maps aim to fulfil? Were 16^th century world maps only symbolical, or was there any practical use for them (is the only practical use for maps finding one`s way around)? Does the symbolic necessarily preclude the practical aspect?
Do world maps in the sixteenth century represent an image of universal, intellectual, theoretical knowledge as opposed to sea charts which can be understood to represent particular case? What is the effect of putting sea charts side by side with world maps? Did sixteenth century cartographers see them as uncombinable? Or did they try before Mercator to do so? What was at stake in implementing Ptolemy´s third projection to sea-charts?

What was the effect of holding the whole world as a unified picture in one´s hands, in one´s sight? Can one associate this effect with the manner in which perspectsive instruments were used to create a sense of objectivity?

Can one bring together Mercator´s attempt to create a map that would be accurate as well as geometrically correct (i.e., that one can find one´s way on a ptolemaic map), and Kepler´s attempt, in the same years (1596-7), to present an astronomical view that combines both a precise calculation of planetary paths and a unified picture of the cosmos?

Is it the case that historians tend to read the origins of perspective through the distorted lens of late 15^th century humanists (i.e., Mannetti´s description of Brunelleschi´s demonstration) or early 16^th century cartographers and painters, who associate Ptolemy´s third projection with perspective? What would be the alternative that Martin Kemp continues to exhort us to find, an alternative rooted specifically in the available practical and theoretical knowledge of the 15^th c.?

To what extent were sophisticated instruments for panoramic views really used? To what extent did they operate as curiousities and sort of marvelous instruments?