Cartography

simple:Cartography

Cartography (or mapmaking) is the study and practice of making maps or globes. Maps have traditionally been made using pen and paper, but the advent and spread of computers has revolutionized cartography. Most commercial quality maps are now made with map making software that falls into one of three main types; CAD, GIS, and specialized map illustration software.

Maps function as visualization tools for spatial data. Spatial data is acquired from measurement and can be stored in a database, from which it can be extracted for a variety of purposes. Current trends in this field are moving away from analog methods of mapmaking and toward the creation of increasingly dynamic, interoperable maps that can be manipulated digitally. The cartographic process rests on the premise that there is there is an objective reality and that we can make reliable representations of that reality by adding levels of abstraction.

Table of contents
1 History
2 See Also
3 Reference

History

The oldest known map dates from the 5000s BC. These more primitive maps emphasize topological relationships such as connectedness, adjacency and containment.

A major development in mapmaking occurred with the advent of geometry which was first used in Babylonia around 2300s BC. An engraved map of the holy city of Nippur, from the Kassite period (14th - 12 centuries BCE) of Babylonian history, was found at Nippur [1]. The Egyptiansians later used geometry to survey land and to resurvey it after the periodic flooding of the Nile obscured the property borders.

The ancient Greeks added a great deal to the art and science of cartography. Strabo (c. 63 BCE - c CE 21) is credited as the father of geography because he wrote "Geographia" in which he documented and criticized the works of others (most of whom would not be known today had Strabo not mentioned them). Thales of Miletus thought that the earth was disk and was supported by water in around 600 BC. Anaximander of Miletus theorized that the earth was cylindrical also about the same time. In 288 BCE Aristarchus of Samos was the first to say that the sun was the center of universe (see heliocentric theory). And in approximately 250 BC Eratosthenes of Cyrene estimated the circumference of the earth to within 15% of the modern-day accepted value.

Pythagoras of Ionia, who was the founder of a mathematical cult that developed many number-based superstitions that later became the basis of mathematics, was the first notable person to say that the earth was a sphere. Aristotle later provided arguments in support of this idea. Those arguments can be summarized as follows:

  • The lunar eclipse is always circular.
  • Ships seem to sink as they move away from view and pass the horizon.
  • Some stars can only be seen from certain parts of the earth.

The Greeks also developed the science of map projections, which are methods of representing the curved surface of the earth on a plane. Eratosthenes, Anaximander, and Hipparchus are credited with developing the concept of longitude and latitude, and Eratosthenes seems to have developed the equirectangular map projection around 200 BC. Claudius Ptolemy developed map projections as well, including the equidistant conic around 150 BC.

During the middle agess of Europe intellectual thought tended toward religion. While scientific cartography advanced in some ways, such as Roger Bacon's investigations of map projections and the appearance of portolano and then portolan charts for plying the European trade routes, there was little impetus for systematic study of cartography. Most world 'maps' of the period were Christian cosmological diagrams that were not intended to be rigorous geographical representations. They were typically rectangular or circular and followed the style of the so-called "T and O map." This world map represented the land as disk-shaped and surrounded by Ocean. The land on the map was divided into three parts by a T shape in which Asia occupied the top of the T area, Europe the bottom left and Africa the bottom right. Dogma also dictated that one son of Abraham colonized each division. The Chinese during this time were using a rectangular coordinate system which was far more accurate and useful.

The discovery of the West by Europeans and the subsequent effort to control and divide up those lands necessitated the invention of scientific mapping methods. The trend of globalism that was started with the Age of Exploration would continue during the Renaissance. This would, in turn, would eventually lead to the Enlightenment in which probability theory, a concern for accuracy, and a desire to classify the world would further develop scientific mapmaking. The concept of distribution, in which systems are characterized and analyzed, and ecological thinking, in which the interrelationships between objects are studied and predictions are made about future behavior, would revolutionize cartography in later centuries.

Technological Changes

During the development of cartography, technology was changing, and continues to change, in order to meet the demands of new generations of mapmakers and map users. The first maps were manually constructed with brushes and parchment and therefore varied in quality and were limited in distribution. The advent of magnetic devices, such as the compass and much later magnetic storage devices, allowed for the creation of far more accurate maps and the ability to store and manipulate them digitally.

Advances in mechanical devices such as the printing press, quadrant and vernier allowed for the mass production of maps and the ability to make accurate reproductions from more accurate data. Optical technology, such as the telescope, sextant and other devices that use telescopes, allowed for accurate surveying of land and the ability of mapmakers and navigators to find their latitude by measuring angles to the North Star at night or the sun at noon.

Advances in photochemical technology, such as the lithographic and photochemical processes, have allowed for the creation of maps that have fine details, do not distort in shape and resist moisture and wear. This also eliminated the need for engraving which further shortened the time it takes to make and reproduce maps.

In the mid to late 20th century advances in electronic technology have led to a new revolution in cartography. Specifically computer hardware devices such as computer screens, plotters, printers, scanners (remote and document) and analytic stereo plotters along with visualization, image processing, spatial analysis and database software, have democratized and greatly expanded the making of maps.

See Also

Reference

  • Fran Evanisko, American River College, lectures for Geography 20: "Cartographic Design for GIS", Fall 2002



copyright 2004 FactsAbout.com