How Maps Work Cathy Moulder Director of Library Services, Maps, Data and GIS McMaster University Library

Agenda  Some map basics  A little bit about maps as social constructs  Some interesting but random nuggets of information about the kinds of maps in His Highness Dr. Al Qassimi’s collection

Map Basics  A map is a two-dimensional graphic representation of the earth’s surface  Maps are created to record and communicate geographic information (ie info about places, locations, distance, proximity, adjacency, distributions, spatial relationships, etc.)

Parts of a map

Cartouche Sayer 1763 Acc # 9284

Directional device  Directional info became a requirement during the age of exploration  Expressed by wind heads, compass roses and rhumb lines on charts  Modern equivalent is a simple north arrow  Western convention, many other cultures did not put North at the top of the map

Scale  Scale = how the map on paper represents the same area on the real earth  Three ways of expressing scale: verbal, visual and representative fraction

Projection

Attempting the impossible...

Maps are socially constructed...  They reflect choices about what is included, what is not included and how things are portrayed  They reflect the cartographer and his society  They are intended to influence the viewer’s perception  Dr. Slot’s lecture and Dr. Al Qassimi’s purpose

Earliest maps = ephemeral materials and practical survival

Maps are deceptively simple

Maps reflect contemporary knowledge Jansson 1636? Acc #

Maps reflect contemporary knowledge So, geographers in Afric maps, With savage pictures fill their gaps And o'er unhabitable downs Place elephants for want of towns. - Jonathan Swift Rasmusio 1606 Acc #

Maps reflect discoveries & new knowledge Waldseemuller [1522] Acc #

Maps reflect fears and angst De Jode 1593 Acc #107270

Maps reflect wishful thinking Du val 1664 Acc #

Maps reflect political domination

Maps reflect political ambition

Maps reflect sovereignty

Maps present different perspectives

Dr. Al Qassimi’s collection  Considered to be one of, if not, the best in the world for this geographic area  Small travelling subset  Collector focus: Persian Gulf, State of Sharjah, Ptolemaic maps

Claudius Ptolemy  Greek/Egyptian scientist, AD  Greek world maps before Ptolemy do not survive but are described in the Illiad  Spherical nature of the earth first argued 6 th C BC, largely accepted 5 th C BC  First projection probably Hipparchus 2 nd C BC  First terrestial projection = Ptolemy  Conic projection family, example catalogue p. 14

Ptolemy’s sciences  14 of Ptolemy’s works survive  Geographia = standard authority on mathematical geography for 14 centuries – mathematically descriptive way of plotting the known world  Book 1 = general principles of mathematical cartography including projections, Books 2-7 = tables of lat/longs for many places in the world  The tables had many errors but the excellence of the projection methods was lasting

Geographia in the Renaissance  Resurgence in accurate map demand for navigation and in the science of projection  Earliest surviving copies are in Byzantine manuscripts 13 th and 14 th centuries  Other than a few woodcut maps, the map printing press was brought into service to disseminate the maps of Ptolemy  Earliest maps printed from copper plates  Probably the first maps that Italian and German readers had ever seen  31 Latin or Italian editions were printed before 1600

Geographia in the Renaissance  “The remarkable legacy of Ptolemy was the transmission of the Hellenistic geographical science to Arabic culture and thence to medieval Europe.” – Wallace & Robinson, Cartographic Innovations 1987: 177

Portolan charts  Examples catalogue pages 56 and 180  ‘Portolano’ refers to written sailing directions  Extended to atlases and charts for sea navigation  Originally the specialty of Italian and Portuguese cartographers  evolved to include the influences of Ptolemy and new coastal knowledge recorded by explorers

Portolan charts  Compass invented circa 1200  Relative despite “compass” marks until the development of Mercator projection 1599  Continued to be used until the invention of accurate longitude in late 1700s  “Armchair navigators”?  “A few early Arabic examples survive” early 14 th C?

Coronelli globe gores  Examples catalogue pages 90 and 92  Vincenzo Maria Coronelli ( ), Italian  “Greatest globe maker of all times”, globes for princes and wealthy patrons  Prepared for terrestrial globe 1688? Size of gore will indicate diameter of globe?  Look for dedications (more likely in ocean areas)?

A few good resources…  Manasek, Collecting Old Maps  Wallis & Robinson, Cartographic Innovations: An International Handbook of Mapping Terms to 1900  Campbell, Map History / History of Cartography