Humble Beginnings

The art of mapmaking, or cartography, began centuries before the Christian Era, when the Babylonians drew maps on clay tablets, of which the oldest specimens found so far have been dated about 2300 BC. This is the earliest positive evidence of graphic representations of parts of the Earth; it may be assumed that mapmaking goes back much further and that it began among nonliterate peoples. It is logical to assume that men very early made efforts to communicate with each other regarding their environment by scratching routes, locations, and hazards on the ground and later on bark and skins.

The earliest maps must have been based on personal experience and familiarity with local features. They doubtless showed routes to neighbouring tribes, where water and other necessities might be found, and the locations of enemies and other dangers. Nomadic life stimulated such efforts by recording ways to cross deserts and mountains, the relative locations of summer and winter pastures, and dependable springs, wells, and other information.

Markings on cave walls that are associated with paintings by primitive man have been identified by some archaeologists as attempts to show the game trails of the animals depicted, though there is no general agreement on this. Similarly, networks of lines scratched on certain bone tablets could possibly represent hunting trails, but there is no conclusive evidence that the tablets are indeed maps.

A (Slightly) More Modern Approach

A reformation of cartography that evolved during the 18th century was characterized by scientific trends and more accurate detail. Monsters, lions, and swash lines disappeared and were replaced by more factual content. Soon the only decorative features were in the cartouche and around the borders. The map interiors contained all the increasing information available, often with explanatory notes and attempts to show the respective reliabilities of some portions.

In earlier productions by individual cartographers or small groups, personal judgments determined the nature of the end product, usually with due respect for conventional standards. Map design for large programs, such as the various national map series of today, is quite formal by comparison. In most countries, the requirements of official as well as private users are carefully studied, in conjunction with costs and related factors, when considering possible changes or additions to the current standards.

The requirements of military agencies often have a decisive influence on map design, since it is desirable to avoid the expense of maintaining both civil and military editions of maps. International organizations and committees are additional factors in determining map design. The fact that development of changes in design and content of national map series may become rather involved induces some reluctance to change, as does the fact that map stocks are usually printed in quantities intended to last for 10 or more years. Also, frequent changes in treatments result in extensive overhauls at reprint time, generating inconsistencies among the standing editions.

GIS Technology Begins to Develop

NASA launched its first Geodynamics Experimental Ocean Satellite (GEOS 1) in 1965; it then sent up GEOS 2 in 1968. In 1970, 43 stations in 23 countries made observations. The aim was to provide a unified three-dimensional framework connecting all landmasses of the world within an accuracy of 10 meters. In 1971 an International Satellite Geodesy Experiment program using the GEOS 2 included most major nations.

The United States launched the first Earth Resources Technology Satellite (ERTS) in 1972. In the polar orbit at an altitude of about 910 kilometres, it transmitted to the Earth multispectral images that provided data to hundreds of scientific investigators in many disciplines: agriculture, forestry, mineral and land resources, land use, and water and marine resources. ERTS 1 was renamed Landsat 1, and in January 1975 Landsat 2 was orbited successfully. The two spacecraft are 180 apart in orbit, thereby providing a view of the same local area with the same sun angle every nine days. By 1981 the Global Positioning System (GPS) became operational. In 1982 the new Landsat D series was introduced with the launch of Landsat 4 and in 1984 with Landsat 5. These satellites retained the multispectral scanner used on the first three Landsats but replaced the black-and-white cameras with a thematic mapper that viewed the Earth in several bands of the deep infrared spectrum. Geographic Resources Analysis Support System development began in 1985 in the US Army Construction Engineering Research Laboratories.

Other Earth observations were made by the Shuttle imaging radar, demonstrating the ability of radar to map terrain below vegetation. In addition, radar even made possible the detection of ancient riverbeds below desert sands in the Sahara.

Continue