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The Shape of the World: The Mapping and Discovery of the Earth

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"In centuries past, some thought the world was flat, or rested on the back of a turtle; for others, earth was a perfect sphere locked tightly into the heart of other spheres. But its true shape remained unseen by human eyes untikl christmas 1968, when the astronauts of Apollo 8 left the earth gravity to circumnavigate the moon. Then, planet earth became known to us all: a ghostly sphere..." The Shape of the World

Late Antiquity Astronomy:
The Hellenized Egyptian Capital, Alexandria developed 'New Mathematics' that enabled men to travel by land and overseas, measured the distance to the farthest stars, and estimated the number of sand grains in the universe. Alexandrine Astronomers were eventually able to measure by indirect means the radius of the earth, the diameter of the sun and moon and the distance to the moon, the sun, the planets, and the stars. Aristarchus virtually invented modern astronomy; while Euclid wrote the elements of geometry and founded mathematics, and methods of its instruction.
"Alexandria originated the greatest advances of mathematics and along with them the creation of an earth-centered model of the orbits of the planets sound enough to survive ... for the very creator of a new solar system model, Claudius Ptolemy, who wrote ancient astronomy's most encyclopedic work, the Almagest*." Conversing With the Planets
Ptolemy's Almagest is one of the most influential scientific works in history, second only to 'The Elements' by Euclid. A masterpiece of technical exposition, it was the basic textbook of astronomy for more than a thousand years, and still is the main source for our knowledge of ancient astronomy. It develops in a modern format, utilizing medieval Arabic translations to identify and make numerous corrections, adding extensive footnotes that take account of the great progress in understanding the work made in this century, due to the discovery of Babylonian records.

Earth Mapping:
Preparation of most except the largest scale maps, where a flat Earth can be assumed without significant error, demands accurate knowledge of the size and shape of the Earth. The notion that the Earth is spherical in shape was developed by the ancient Greeks. One of the earliest determinations of the size of the Earth, based on its perfect spherical; shape, was made by Eratosthenes the second century B.C. Alexandrian geographer and astronomer. He is noted for devising a system of latitude and longitude, and for being the first known to have calculated the circumference of the Earth. He also created a map of the world based on the available geographical knowledge of the era. He knew that at the summer solstice, the noon sun is directly overhead on the Tropic of Cancer, where the town of Syene (present-day Aswan, Egypt) was located since vertical shadows were cast there at the summer solstice. He also observed that at the summer solstice, angled shadows were cast at Alexandria which is located north of Syene on approximately the same meridian. He measured the angle of the shadow and found it to be 7.2 degrees, or about 1/50 of a full circle. He measured (or possibly estimated) the distance between Alexandria and Syene at 5000 stadia and therefore determined that the circumference of the Earth was 50 times 5000 or 250,000 stadia. Given modern estimates of the length of a stadia, this is remarkably close to the Earth's equatorial circumference of 40,075 km.

Maps of Ancient world:
Around 150 AD, Claudius Ptolemy, an Alexandrine geographer, and astronomer, compiled an encyclopedia of the ancient world from the archives of a legendary library in Alexandria, Egypt. His eight-volume Geography included extensive maps of the known world, all based on a curved globe. Unfortunately, learning and intellect went out of fashion in Europe between 400 and 1200 AD. The storehouses of Alexandrian scientific knowledge were lost to Western society with the advent of the Dark Ages. Sea monsters and Vikings ruled the seas, and ships that ventured too far from shore were sure to fall off the edge of a flat Earth. Maps made in that time were based on religious beliefs or superstitions, not on observations, calculations, or scientific inquiry. Rectangular maps of the Earth represented the "four corners of the Earth." Circular maps usually placed the birthplace of Christianity, the holy city of Jerusalem, at the center of the world.

Cartography and Globes:
Cartographers have long known that the images on maps often do not reflect the actual shapes and relative sizes of continents and seas. In the widely used map projection drawn in 1569 by the Flemish cartographer Gerardus Mercator, Greenland is exaggerated 16 times and appears to be bigger than South America, even though it is only about the size of Mexico. The National Geographic's Van der Grinten projection, which has been used for the past seven decades, shows Alaska blown up to five times its real size, making it appear roughly equivalent of Brazil, which is actually six times as large. Garver acknowledged, "The only accurate map is a globe." But globes are awkward to carry around. And no matter what gimmick is used, drawing the surface of a sphere on a flat plane results in distortion. Anyone who tries to flatten a whole peel of an orange can imagine the difficulty. The features of a globe cannot be transferred accurately to a flat map. If the shapes of continents are correct, the sizes are wrong; a system that is accurate at the equator is hopeless at the poles. Endless variations have been tried, from circles to ovals, rectangles, hearts and butterflies, all of them flawed. Competing versions have triggered emotional controversies. "Cartographers since Ptolemy have wrestled with the problem," says Arthur Robinson, professor emeritus of geography at the University of Wisconsin, who devised the projection used in the Geographic Society's new map. "Alas, there is no perfect solution."

Map-makers & Projections:
Most map makers devise projections with mathematics. "Mapmaking is as much an art form as a science," argues Robinson, the dean of U.S. cartographers. Thus he began by visualizing the way each country ought to look on a map, then turned to mathematics to delineate its shape. "What I really did," says Robinson, "was create a portrait of the earth." There are still distortions in his map, both at the equator and at the poles, "Only at these latitudes are the size and shape relationships accurate, as they are on the globe." To convey a sense of roundness, the map has been given curved sides. The Geographic Society's new map, like its predecessor, is centered on Europe, in part it is "the best balance available between geography and aesthetics."

Of Continents and Seas:
In the widely used map projection drawn in 1569 by the Flemish cartographer G. Mercator, Greenland is exaggerated 16 times. The National Geographic's Van der Grinten projection, which has been used for the past seven decades, shows Alaska blown up to five times its real size, appearing roughly equivalent of Brazil, which is actually six times as large. "The only accurate map is a globe," acknowledges Garver, But globes are awkward to carry around. The features of a globe cannot be transferred accurately to a flat map. Endless variations have been tried, from circles to ovals, rectangles, hearts and butterflies, all of them flawed. Competing versions have triggered emotional controversies. "Cartographers since Ptolemy have wrestled with the problem," says Arthur Robinson, professor emeritus of geography at the University of Wisconsin, who devised the projection used in the Geographic Society's new map. "Alas, there is no perfect solution."
Most mapmakers devise projections with mathematics -- and nowadays the computer. But Robinson, who is considered the dean of U.S. cartographers, decided to take a different approach. "Mapmaking is as much an art form as a science," he argues. Thus he began by visualizing the way each country ought to look on a map, then turned to mathematics to delineate its shape. "What I really did," says Robinson, "was create a portrait of the earth."

Early maps exhibition:
An exhibition of early maps and sea charts at Scandinavia House offers both literal and mind-expanding lessons. It presents 76 maps, atlases and sea charts that depict the world, Europe, Scandinavia and Norway, dating from the late 15th century to the late 18th century. The displays begin with an impressive wall of woodblock maps of Europe and the world from around 1500. Most are based on the atlas of the great Greek geographer Ptolemy, the coordinates for which resurfaced during the Renaissance. Although it is not known if the 26 maps of the Roman empire whose coordinates Ptolemy plotted were actually made during his time (second century A.D.), Italian cartographers put them to immediate use: Ptolemy's ''Geographia,'' an influential atlas, was published in Italy in the late 15th century. Included here is a Ptolemaic map published in Ulm in 1482; it isolates Scandinavia for the first time, surrounding its irregular land masses with deep blue water. To its right is one of the first maps of Europe to replace Ptolemy's model with a more accurate projection of the continent, a woodblock published by Schedel in Nuremberg in 1493, a year after Columbus set sail.

Topography & Topographers:
The location of mountains, ocean trenches, ridges, and coastlines are all keys to the analysis of Earth's dynamic processes. Topography is a fundamental databasis available to Earth scientists, to examine the spatial relationships between areas of high topography. They can accordingly study how these relationships arise from plate interactions, that could cause earthquakes, and volcanoes. The resolution of the topographic data set is approximately one km, so a variety of features related to the underlying geology, geologic history and dynamic earth processes that create topography could be enabled for study. The Christian Topography was written over a period of years: the first five books were compiled for a friend, Pamphilus, and the remainder as occasion arose: partly to answer critics of the original books, partly to provide evidence from earlier writers for the truth of his understanding of scripture, and (bk. XI) to describe the animals and other curiosities he had encountered in his travels, especially to the island of Taprobane (Ceylon).

Cosmas Indicopleustes:
Indicopleustes, 'India-voyager,' of Alexandria was a Greek sailor in the early 6th century who travelled to Ethiopia, India and Sri Lanka. He then became a monk, probably of Nestorian tendencies, and around 550 AD wrote a strange book, copiously illustrated, which is the text presented here. There can be few books which have attracted more derision, mixed with wonder, than the Christian Topography of Cosmas Indicopleustes. It advances the idea that the world is flat, and that the heavens form the shape of a box with a curved lid.The latter pages of his work are devoted to The approach to scripture is discreditable, and the conclusion made simply wrong.The book is rebutting the criticism of his fellow-monks, that what he was saying was wrong.

The Shape of the World:
Above concise introduction, could be expanded magnificently, with plenty of visual aids, photos and maps, in the beautifully illustrated companion to a six partPBS TV series , a classic documentary that tells the story of exploring and measuring plant earth, with attempts to draw maps for its continents and seas. This amazing book is one of few to mention my synonym Cosmas, but the book surveys the total history of mapmaking from Pythagoras, and Ptolomyto Galileo, up to the NASA space photos of our plant.
The book has reproductions of many of the landmark maps of the ancient and medieval world, with stories of discoverers as Columbus and Magellan who sailed unknown seas, which created the magic of our childhood, that you could recapture now.