International Map of the World

Origins - From the 1860's to the 1980's

The late nineteenth century and the early twentieth century witnessed the beginning of globalization and the dream of constructing a single, internationally recognized map of the world, based on a common scale and universally agreed conventions. The idea first came to light in the 1860's from Sir Henry James, Director of the British Topographical Department. The belief that the 1:1 million scale represented the most sensible option for an international map reflected the success of mid-century maps depicting the emerging regional economic and political federations at this scale.

In August 1891, a proposal to construct a standard 1:1 million international map was suggested by the German geographer Albrecht Penck in a presentation to the Fifth International Geographical Congress in Bern, Switzerland. Using a common projection, the series would topographicaly map segments of the globe in 1 million times smaller sheets, which would allow scientists and students alike to explore world-wide comparisons for the first time. A set of ground rules emerged that were ratified at an international conference organized in London by the Ordnance Survey and the British Foreign Office in November 1909. In all, about twenty sheets were published in accordance with the 1909 resolutions before WWI. About 400 more sheets were completed before World War II, supervised by the League of Nations. After the war, the United Nations assumed supervision and by the time this project came to an end in 1987, only about 850 sheets were completed.


The map series is known as the International Map of the World (IMW) or the Millionth Map. The original IMW uses a simple Polyconic projection. In later sheets the projection used was Lambert Conformal Conic which shows features in the 'correct shape' with angles on the map maintained correctly. Greenwich is the prime meridian, and the metric system is used as the measure of distance. Each map sheet, corresponding to four degrees of latitude and six degrees of longitude, has a scale of 1:1,000,000 (1 centimeter on the map represents 10 kilometers or 1 inch equals 15.78 miles). To provide geographic coverage of the entire world's land area would have required 974 map sheets (each measuring approximately 18" by 24").

The modified Polyconic map projection designed by Lallemand and adopted for the IMW between 1909 and 1962 has two meridians and two parallels which are true to scale. Although the projection is neither equal-area nor conformal, scale does not vary more than 0.06% throughout the quadrangle.

(More tech stuff coming "real soon now" - don't hold your breath though [Grin]

How I did This

(placeholder) Methodology, Projections, Guessing Datum, etc.