H-110. The Art & Science of Cartography, 200–1550

John Hessler

The foundations of modern cartography begin with the researches of the Greek astronomer Claudius Ptolemy in the second century and the re-discovery of his texts in the late Middle Ages and Renaissance. Ptolemy invented the concepts of latitude and longitude and also the idea of a map projection. Early mapmakers used Ptolemy’s ideas and extended them to account for the new discoveries made by explorers in the late fifteenth and early sixteenth centuries. These early modern maps also took full benefit of the developments in mathematics, navigation and astronomy to display the world visually in innovative ways.

Parallel to the tradition of Ptolemy was another and more mysterious form of cartography that appeared around 1250 and died out in the mid-sixteenth century. These maps took the form of a medieval sailing chart and were made for use on board trading vessels that sailed the Mediterranean Sea. Charts like these, called portolans, generally survive as large manuscript maps on vellum and derive from a mapmaking tradition that does not take into account map projections and whose original construction methods still baffle scholars today.

This course will introduce students to the earliest forms of cartography and discuss both the scientific and artistic innovations that made these two kinds of mapmaking possible. We will examine in detail the construction methods of some of the masterpieces of Renaissance cartography, such as the 1507 and 1516 world maps by Martin Waldseemüller, and other examples of early cartography found in the Library of Congress. Students will look closely at the making of portolan charts and take full advantage of new analytical research on their make-up. In addition to close scrutiny of the maps themselves, class discussion and reading will consider medieval and early Renaissance theories of the earth and the relationship of cartography to contemporary developments in astronomy and navigation, as well as the social and cultural aspects of patronage and production.

Late in the course, students will be introduced to digital humanities analysis tools, such as MapAnalyst, and learn to use these new computational methods in order to help date and understand the complex notions of error and knowledge transmission that are at the foundations of modern cartography.

There are no prerequisites for this course, except an interest in early maps and a willingness occasionally to work with and discuss abstract concepts. In their personal statements, applicants should describe the nature of their developing interest in the history of the map, their expectations of the course, and the purposes to which they propose to put the knowledge gained from their participation.

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John Hessler teaches this course.
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John Hessler

John Hessler

John W. Hessler is a Specialist in Computational Geography and Geographic Information Science at the Library of Congress.

A Fellow of the Royal Geographical Society, he is the founder of the Election Labs for the Study of the Mathematics of Voting, and is a Lecturer in the Graduate School of Advanced Studies at Johns Hopkins University. He has taught seminars in advanced spatial and cartographic analysis, category theory, game theory and Arrow’s theorem, and the mathematical analysis of gerrymandering.

His current research focuses on the use of renormalization group and random matrix methods to study the mysterious mathematics and computational function of deep learning algorithms and networks. He is also interested in the theory of Markov Chains and their application to mapping, redistricting and gerrymandering problems, and in the application of supercomputing GIS to the study of voting systems around the world.

He is the author of more than one hundred books and articles, including MAP: Exploring the World; The Naming of America: Martin Waldseemüller’s 1507 World Map and the Cosmographiae Introductio; A Renaissance Globemaker’s Toolbox: Johannes Schöner and the Revolution of Modern Science, 1475–1550; Seeing the World Anew: The Radical Vision of Martin Waldseemüller’s 1507 and 1516 World Maps. His work has been featured in many national media outlets including the New York Times, Washington Post, Discover Magazine, the Atlantic’s CITYLAB, the BBC, CBS News and most recently on NPR’s “All Things Considered” and in WIRED. An avid mountaineer, he is also an occasional contributor to Alpinist Magazine, and is currently at work on a book entitled Algorithmic Democracy: Mathematical Approaches to the Study of Gerrymandering.


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