Mapping exhibition at National Library of Australia delves into a new world

THE history of mapping, this great adventure of the human mind, is the subject of a remarkable exhibition at the National Library of Australia.

Ptolemaic map (1454) that belonged to Cardinal Bessarion. Picture: Biblioteca Nazionale Marviana, Venice

ASK a child - or even an adult - to draw you a plan of their house or apartment, and you will discover how hard it is to give an objective account of these familiar spaces. We could walk around them with our eyes closed, and we are surprised to find how hard it is to set them down on paper with correct proportions and alignments; we know the hall turns left at this point, but we discover we are not sure how it hugs the kitchen or where the bathroom is in relation to either.

If we attempt something a bit more ambitious, like a country property, with the road in, the house and garden, the various outbuildings, the correct course of the river and the location of the surrounding hills, we begin to realise it is almost impossible to produce an accurate map from memory, and far from easy even when we are on the spot and can check distances and orientations.

Imagine, then, mapping a country, a sea or the world, based entirely on observation gathered in the course of travel and the inference of directions and intervals from the movement of the sun, the planets and the stars. And imagine this when much of your information is based on the reports of earlier travellers and when large parts of the globe have never yet been traversed by anyone.

The history of this great adventure of the human mind, from the Middle Ages through the great age of exploration until the task was more or less completed about two centuries ago, is the subject of a remarkable exhibition at the National Library of Australia. And here it should be noted - since we have recently discussed the difficulty of obtaining first-rate loans for exhibitions in this country - that the library should be congratulated for the masterpieces it has secured for this exhibition.

The prelude to the story is the medieval mappa mundi tradition, coincidentally also the subject of a fascinating and beautifully illustrated book by Alessandro Scafi, Maps of Paradise (British Museum, 2013). The question of locating the Garden of Eden on a map of the real world leads to a broader consideration of what map-making meant to this earlier age. These medieval works were certainly not charts for the use of sailors - the seas are crushed into narrow channels between land masses - but compendiums of traditional knowledge about the parts of the world, and as much summations of human history as works of geography.

Thus where we are accustomed to maps oriented to the north, the mappa mundi usually had east at the top; this was the traditional location of the earthly paradise, and the movement from top to bottom - and the Pillars of Hercules in the west - was also roughly a timeline of human history. To modern eyes, used to thinking of the Mediterranean as stretching from left to right, it is extraordinarily disconcerting to find it extending up and down: if you think of your home again, it is as though all the left and right-hand turns were switched by 45 degrees.

The exhibition includes maps oriented to the east in a series of volumes, as well as others to the south - and, strangely enough, it is easier to read the upside-down image because it is a simple reversal, although just as disturbing that the North African coast, for example, is above Italy and France. We also find, coinciding with this tradition, another way of imaging the world, inspired by late antique author Macrobius, who described it as a globe with frigid zones at the poles and two temperate zones divided by the torrid zone around the equator, long thought to be impossible to traverse. These zonal globes tend to be oriented to the north; the ones in the exhibition have the Latin septentrio inscribed at the top to avoid confusion.

Contrary to a persistent myth, the ancients knew very well that Earth was a sphere, and Hellenistic scientist Eratosthenes had even worked out its circumference with considerable accuracy. The great geographer and astronomer Ptolemy, in the second century AD, had summed up ancient knowledge of the subject in a treatise that was little known during the early Middle Ages but rediscovered in the Renaissance. Among other things, he explained, following Marinus of Tyre, how to grid the globe with lines of latitude and longitude, and gave the geographical co-ordinates for more than 8000 locations. A Renaissance map reconstructed on the basis of Ptolemy's data not only represented a revolution in objective accuracy but opened out the compacted seas as though inviting navigation and exploration.

The Ptolemaic map in the exhibition (1454) belonged to Basilios Cardinal Bessarion, the Greek scholar and prelate who came from Byzantium and settled in Italy. Covering a region from the Atlantic to Indochina, it is spread over two pages of a magnificent codex, and the preciousness of the knowledge it preserves is underscored by the almost breathtaking luxury of the production, with borders of gold leaf and the sea painted in lapis blue. The names of seas, islands and cities are inscribed in Greek in gold lettering. Interestingly, although the Garden of Eden was not part of Ptolemy's geography, an exquisite pair of Adam and Eve, driven out of Paradise, is included just off the east edge of the map proper and on the golden border.

The Bessarion Ptolemy is one of the treasures of the Biblioteca Marciana in Venice, itself originally founded with the bequest of the cardinal's library; another and even more spectacular one is the immense world map of Fra Mauro, also executed in Venice in the middle of the 15th century. Although it incorporates information from Ptolemy and from the extensive practical experience of Venetian seafarers, Fra Mauro's view of the world is still oriented to the south. Brilliantly conceived and exquisitely executed, synthesising medieval tradition and contemporary knowledge of the Mediterranean, it is a precursor to the heroic age of exploration that was to begin just a few decades later and take Europeans to every corner of the globe.

Great maps that incorporate the lessons of these voyages, including one made for Henry VIII and another for his French contemporary Francois I, reveal an entirely new level of detailed, first-hand knowledge of Africa, the Indian Ocean, and the East Indies. But the latter in particular still combines eminently practical information with decorative details such as figures of the wild animals that inhabit the various regions and legendary motifs such as the land of Prester John in Ethiopia or the famous Mountains of the Moon associated with hypothetical reconstructions of the source of the Nile (not properly identified until the end of the 19th century).

Map-making in the later 16th and 17th centuries is dominated by the Dutch, who combined seafaring prowess and the economic innovations of early modern capitalism with a consummate talent for surveying, draughting, engraving and printing. Maps become progressively more accurate and thus reliable as guides into the vast oceans that were as unknown and dangerous as space is to us today. At the same time they became favourite ornaments of wealthy households, as we see in the background of several paintings by Vermeer, evoking patriotic pride in seamanship and recalling the source of national and personal wealth.

One of the greatest practical problems of map-making was how to project the spherical shape of the Earth, with Ptolemy's network of latitudinal and longitudinal lines, on to flat charts for the purposes of navigation. The most direct and proportionally accurate way of representing this system on a flat surface was to depict the world as a circle, and this is the typical pattern of twin hemispheres that we find on most of the maps used for decorative, or at least for non-navigational purposes.

For marine charts, one of the greatest innovations of the time was Gerard Mercator's new projection (1569), which opened up and flattened the polar extremities of the globe, so that lands near each pole were shown as larger than their true scale (thus Russia and Canada, and even Australia, seem bigger than they really are); its enormous advantage, however, was that all latitudinal and longitudinal lines intersected at right angles, and all compass directions on the chart became straight lines.

But another difficulty remained: although it was relatively easy to work out the latitude one was on, it was hard to be certain about the distance between lines of longitude; and this is why so many early maps overestimate or underestimate this dimension - in Diego Ribeiro's 1529 Planisphere, for example, the coastlines of the Indian Ocean are correct in many details, yet Africa is too wide and India much too narrow.

The solution to this problem, the marine chronometer, which allowed one to know exactly what time it was at the prime meridian at Greenwich, London, came with the last phase of the heroic age of navigation, which was dominated by the British and became increasingly focused on the mapping of Australia and the Pacific. Almost from the beginning, Australia is an intriguing presence in the exhibition, for the ancients had predicted the existence of a southern land so early explorers were always on the lookout for it; when the coast of western Australia was glimpsed by the Dutch - or perhaps even earlier - it was a natural candidate, and in many early maps it is speculatively joined to Antarctica.

Gradually, Dutch navigators added pieces to the map of the continent in the first half of the 17th century, though several maps concur in dating its discovery to Abel Tasman's voyage in 1644. Extraordinarily, no attempt was made to colonise the land for almost 200 years - indeed there is no part of the world that Europeans were so reluctant to occupy. It seemed poor, arid and unpromising for settlement, it was at the ends of the earth, and the native inhabitants had nothing anyone else wanted, so there was no basis for trade.

But Australia also remained an incompletely defined land, an open, gaping outline, uncharted to the east, on a century of world maps. It was only after James Cook, in the course of his extraordinary voyages armed with the new chronometer, had completed the perimeter of the continent and in the process discovered its most habitable parts, that settlement was contemplated. Yet Emanuel Bowen's map of almost a generation earlier, in 1744, had already asserted that the famous terra australis was "no longer incognita" and that "whoever perfectly discovers and settles it will become infallibly possessed of territories as rich, fruitful and as capable of improvement as any that have hitherto been found out".

Mapping Our World: Terra Incognita to Australia, National Library of Australia, Canberra, to March 10.