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How Maps Work Cathy Moulder Director of Library Services, Maps, Data and GIS McMaster University Library
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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
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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.)
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Parts of a map
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Cartouche Sayer 1763 Acc # 9284
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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
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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
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Projection
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Attempting the impossible...
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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
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Earliest maps = ephemeral materials and practical survival
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Maps are deceptively simple
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Maps reflect contemporary knowledge Jansson 1636? Acc # 107235
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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 # 107202
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Maps reflect discoveries & new knowledge Waldseemuller [1522] Acc # 107215
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Maps reflect fears and angst De Jode 1593 Acc #107270
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Maps reflect wishful thinking Du val 1664 Acc # 107005
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Maps reflect political domination
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Maps reflect political ambition
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Maps reflect sovereignty
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Maps present different perspectives
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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
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Claudius Ptolemy Greek/Egyptian scientist, 100-170 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
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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
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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
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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
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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
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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?
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Coronelli globe gores Examples catalogue pages 90 and 92 Vincenzo Maria Coronelli (1650-1718), 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)?
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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 http://www.maphistory.info/index.html http://www.maphistory.info/index.html
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