However, it was much ahead of its time, since the old navigational and surveying techniques were not compatible with its use in navigation. The development of the Mercator projection represented a major breakthrough in the nautical cartography of the 16th century. However, the mathematics involved were developed but never published by mathematician Thomas Harriot starting around 1589. The first mathematical formulation was publicized around 1645 by a mathematician named Henry Bond (c. Various hypotheses have been tendered over the years, but in any case Mercator's friendship with Pedro Nunes and his access to the loxodromic tables Nunes created likely aided his efforts.Įnglish mathematician Edward Wright published the first accurate tables for constructing the projection in 1599 and, in more detail, in 1610, calling his treatise "Certaine Errors in Navigation". Mercator never explained the method of construction or how he arrived at it. This title, along with an elaborate explanation for using the projection that appears as a section of text on the map, shows that Mercator understood exactly what he had achieved and that he intended the projection to aid navigation. Mercator titled the map Nova et Aucta Orbis Terrae Descriptio ad Usum Navigantium Emendata: "A new and augmented description of Earth corrected for the use of sailors". In 1569, Gerhard Kremer, known by his trade name Gerardus Mercator, announced a new projection by publishing a large planispheric map measuring 202 by 124 cm (80 by 49 in) and printed in eighteen separate sheets. If these sheets were brought to the same scale and assembled, they would approximate the Mercator projection. In 1537, he proposed constructing a nautical atlas composed of several large-scale sheets in the cylindrical equidistant projection as a way to minimize distortion of directions. Portuguese mathematician and cosmographer Pedro Nunes first described the mathematical principle of the loxodrome and its use in marine navigation.
The projection in use was the equirectangular projection. However, this was a simple, and common, case of misidentification. Joseph Needham, a historian of China, wrote that the Chinese developed the Mercator projection hundreds of years before Mercator did, using it in star charts during the Song Dynasty. Snyder amends his assessment to "a similar projection" in 1994.
However, given the geometry of a sundial, these maps may well have been based on the similar central cylindrical projection, a limiting case of the gnomonic projection, which is the basis for a sundial. The projection found on these maps, dating to 1511, was stated by Snyder in 1987 to be the same projection as Mercator's.
#Compass rose puzzle portable#
German polymath Erhard Etzlaub engraved miniature "compass maps" (about 10×8 cm) of Europe and parts of Africa that spanned latitudes 0°–67° to allow adjustment of his portable pocket-size sundials. There is some controversy over the origins of the Mercator. 5.3 Mercator projection transformations.
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