-------- Original Message --------
Subject:        Program and Registration for LOC Portolan Conference
Date:   Wed, 17 Mar 2010 08:08:33 -0400
From:   John W. Hessler <[log in to unmask]>







The program for the Library of Congress' previously announced conference
on Portolan Charts is shown below...the conference is free, but
registration is required...to register e-mail me at [log in to unmask] or Pam
Van Ee at [log in to unmask] .

Re-examining the Portolan Chart:
History, Navigation and Science

Sponsored by the Philip Lee Phillips Society and the
Geography & Map Division of the Library of Congress

May 21st, 2010,  Coolidge Auditorium

Morning Session: History and Navigation, 9:30-11:30

The Marine Chart in the Mappamundi:
Mapping the World in the Later Middle Ages

Evelyn Edson
Professor of History
Piedmont University

        Modern scholars have long been fascinated by the medieval marine
chart: “the first, modern scientific map,” rhapsodized Edward L.
Stevenson in 1911 in his book on sea charts. The contrast with the
mappamundi, with its lively pictures, lengthy legends and unrecognizable
geographical outlines, could not be more striking. One is all business,
the other closer to fantasy. Yet, recent research, pushing back the
origin of the marine chart to 1200, has made it clear that these two map
types flourished side by side, and were consulted and even occasionally
constructed by the same people. The thirteenth century, the period which
shows the first evidence of marine charts, was also the heyday of the
great mappaemuindi, such as the one at Hereford Cathedral.

        Marine charts had a different purpose and scope than a
mappamundi. Limited to the well-known world of the Mediterranean and
Black Sea basins, and eventually the Atlantic coast, they did not
attempt to depict the interior lands, much less the entire world with
its terrae incognitae shown on the mappamundi. And yet, looking from one
to the other, we can see that the lines separating the two forms are not
all that clear. Marine charts may come with explanatory texts, be
burdened with legends that have nothing to do with navigation, or be
ornamented with images of richly caparisoned kings. Itineraries appear
on the Hereford mappamundi, as G. R. Crone observed many years ago, and
by the fourteenth century we have what David Woodward called
“transitional maps,” and more recently, Ramon Pujades has termed
“hybrid maps.” We must look at marine charts and mappaemundi as
contemporaneous products, rather than one being “modern” and the
other more “medieval.”


The Birth and Use of the Navigational Chart

Alison Sandman
Assistant Professor of History
James Madison University

In the sixteenth century, Portolan charts were expanded to meet the new
navigational needs of the Iberian overseas empires, extending them from
the Mediterranean to include first the Atlantic and then the entire
world without meaningfully changing their form.  This brought into focus
several distinct types of problems, which both cartographers and
navigators attempted to solve, often in very different ways.  The
greater extant of the charts highlighted issues of projection, and
arguments about the proper way to reconcile compass bearings with first
latitudes and (eventually) longitudes.   It also forced decisions about
information-gathering, most notably what sorts of information were most
useful (weather patterns, depths and obstacles around the port,
latitudes, landmarks, etc.), who could be trusted to gather that
information, and to what extent branch offices in areas such as the
Philippines could help in developing both charts and navigators with
local expertise, all without experts in the center losing too much
control.   The surviving debates of the sixteenth and early seventeenth
centuries, in revealing the ongoing controversies about cartography and
navigation, can help us understand the always fraught connections
between those making maps and those using them, even as they took
Portolan charts and altered them almost out of all recognition.


The Portolan Chart: Dimensions of the Genre

Richard Pflederer
Independent Scholar
Williamsburg, Va.

Portolan charts are particularly interesting artifacts of the medieval
and renaissance period in that the genre began as plain, functional
tools of work-a-day mariners but eventually evolved into a highly
stylized and decorative art form. Because these charts were initially
intended to be used, abused and discarded, the surviving population
represents a small and probably non-representative subset of the total
production. Nonetheless, we can extrapolate with some confidence,
especially by combining our studies with documentary evidence from a
variety of sources, including manuals covering navigational practices of
the period.

This lecture will offer a definition of portolan charts and touch on
the intelligent speculations on the origins of the genre. It will also
provide a ‘big picture’ view of the surviving population covering
the period from the earliest charts through the 17th century when
printed charts began to dominate. It will also outline the evolution of
production locations, coverage area and decorative styles throughout the
period.

Afternoon Session: Analysis and Science, 1:30-3:30

Bi-dimensional Regression Revisited:
Studying the Mathematical Structure and Form of the Portolan Chart

John Hessler
Fellow of the Royal Geographical Society
Senior Cartographic Librarian
Geography and Map Division
Library of Congress

One of the major open questions and areas of controversy in the history
of the analysis of Portolan Charts is whether or not they are projected.
This question has been addressed in the past by several scholars
including Waldo Tobler, the inventor of the technique of bi-dimensional
regression. In this paper we will look at Tobler’s work and update his
mathematical methods using more advanced radial basis functions and
thin-plate splines to probe the geometric structure and form of Portolan
charts. We will discuss some more modern results, such as those of
Joaquim Gaspar, and show how the techniques of distortion grids and
scale and rotation isoline surfaces can be adapted for comparative
analysis of charts of the period from 1290-1590. I will also highlight
how some more advanced metrics, that I have derived from the field of
statistical shape analysis on Riemann surfaces, can be used to further
determine the error and show the evolution of these early nautical
charts.

Scientific and Image Analysis of Portolan Charts:
Preliminary Results and Methods

Fenella France
Preservation Scientist
Preservation Research and Testing Division
Library of Congress

The scientific assessment and characterization of a range of Portolan
Charts from ca. 1320 - 1665 revealed information about materials used in
the construction of these charts. A range of analytical methods were
utilized in these studies. Carbon-14 dating confirmed the age of the
vellum used. Hyperspectral imaging, which involves taking images of the
charts over a range of wavebands - from the ultra-violet, through
visible, to infrared - utilizes low light, low heat LEDs for
illumination to ensures no damage to the object. Specific
non-destructive characterization of inks, pigments and colorants can be
achieved, including revealing lost and hidden details, as well as
construction marks such as compass points and erasures. This enhances
our knowledge of the object by allowing scholars and researchers to gain
access to information relating to how the charts were created, including
assessments of things like colorants that indicate whether these charts
may or may not be commensurate with the suggested timeframe. The
characterization of the media on the chart can be further confirmed
through the use of additional non-destructive analyses including
portable x-ray fluorescence and x-ray diffraction spectroscopy. This
minimizes the handling of the artifact, and provides additional
information that may allow a source or location for the inks and
colorants to be suggested.

Saturday

There will be an open house in the Geography and Map Division Reading
Room, James Madison Building, Room B-01, on Saturday from 9:30 to noon
where they will display their Portolan Collection.




John W. Hessler
Fellow of the Royal Geographical Society

Senior Cartographic Librarian
Geography and Map Division
Library of Congress
Washington DC
202-707-7223

Website:
http://www.warpinghistory.blogspot.com

What any picture, of whatever form, must have in common
with reality in order to depict it--correctly or incorrectly--
in any way at all, is logical form, i.e. the form of reality.

            --Wittgenstein
               Tractatus Logico-Philosophicus