Mapping the story of a city from past to future


Under the Microscope:Knowing where places are, the distances that separate them, how to get from one place to another, the physical, economic and social characteristics of places, is now something we take for granted, writes Prof William Reville

To get this knowledge we simply consult maps. We can easily forget that the acquisition of this knowledge was a slow and painful process, and a relatively recent one - 500 years ago no one knew what a quarter of the world looked like

Detailed mapping of the world was largely done by Europeans over the period 1450-1900. The names of those who carried out what are often called the voyages of discovery - Christopher Columbus (1451 to 1506), Vasco da Gama (1469-1524), Ferdinand Magellan (1480-1521) and so on - are well known. These voyages should more correctly be called voyages of exploration because, of course, the places "discovered" were already known to and occupied by their indigenous peoples. These voyages were not simply adventures of the human spirit, strongly motivated by a thirst for discovering new knowledge. The immediate motivation of these explorers was mostly worldly-mercenary, rapacious, military and imperial.

When Europeans explored unknown territory they sometimes got invaluable help from the native populations. The difference between the natives and Europeans was that once the Europeans learned the knowledge they recorded it on maps and it became part of conscious world geography. People in London and Amsterdam now had knowledge of Brazil, India, Mexico and so on, while the native people knew only their own environment.

A map is usually a diagrammatic representation of part of the Earth's surface printed on a flat surface, bearing symbols that indicate natural, artificial or cultural features of the area covered. Since the Earth is spherical, to represent the entire surface without distortion a map must have a spherical surface. Such a map is called a globe. A flat map can only represent very small areas of the Earth where the curvature is negligible without significant distortion. To show large portions of the Earth's surface the map must make compromises among areas, distances and direction.

The various methods of making a flat map are known as projections and are classified as either geometric or analytic. Geometric projections are classified according to the type of surface on which the map is assumed to be developed, such as cylinders, cones or planes. Analytical projections are developed by mathematical computation.

In making a cylindrical projection, the surface of the map is regarded as a cylinder that touches the globe only at the equator. Parallels of latitude are extended outwards from the globe to intersect the cylinder as parallel planes. Because the globe is curved, parallels of latitude nearer the poles project onto the cylinder progressively closer together. Projected meridians of longitude are represented as parallel straight lines perpendicular to the equator. After the projection is completed the cylinder is split vertically and rolled out flat. The world is now represented as a rectangle with unequally spaced parallels of latitude and equally spaced parallel lines of longitude. The shapes of areas on the map are increasingly distorted towards the poles, but the size relationships of areas on the map is equivalent to the size relationship of areas on the globe.

The well-known Mercator Projection, developed by the Flemish geographer Gerardus Mercator (1512-1594) is a modification of the cylindrical projection. Directions are represented faithfully on the Mercator map. A navigator can plot a course simply by drawing a line between two points and reading the compass direction from the map.

The surface landmasses of our Earth have now been comprehensively mapped and there is no more need of "voyages of discovery". However, much work remains on the mapping of the floors of the oceans. Of course, the final frontier is the limitless universe beyond Earth where undoubtedly innumerable voyages of discovery will venture one day.

My present interest in maps was pricked by reading recently a very fine example of the geographer's and cartographer's science and art - Atlas of Cork City, edited by JS Crowley, RJN Devoy, D Linehan and P O'Flannagan, (Cork University Press, 2005). This ambitious project was undertaken to mark Cork 's designation as European Capital of Culture in 2005. It presents a range of perspectives on the city and its development over time and is illustrated with more than 200 maps, many specially commissioned for the project.

More than 60 experts from various disciplines - geographers, poets, musicians, botanists, historians, journalists, painters, novelists, photographers, archaeologists climatologists, sociologists, planners and engineers - come together to tell the story of Cork. The city is located in its environmental setting and its development followed from pre history up to the present. The influence of Huguenots, Quakers and Protestant ascendancy in shaping the original streetscape of the city is described as is Cork's significant maritime heritage and the prosperity derived from it. There are chapters on the Royal Cork Institution, UCC, the Famine, Cork's Jewish community, Cork's architecture, the English market, soccer, hurling, road bowling, music, literature, and contemporary Cork issues.

Some interesting facts recorded in the atlas include: Cork county now has the third highest concentration of pharmaceutical companies in the world; in 2002, 5.4 per cent of the population of Cork city was non-Irish or from the UK. Each essay is written in very accessible language and nicely illustrated not only with maps but aerial photographs, satellite images, paintings and illustrations from private and public archives. The atlas is a "must have" not only for every household in Co Cork but for everyone interested in the history, geography and developments of the city. William Reville is associate professor of biochemistry and public awareness of science officer at UCC -