1569

Sea charts, globes, Ptolemy, and the 1500s explosion of Atlantic and Indian Ocean knowledge. Mercator had already made a globe (1541) and been imprisoned for suspected heresy in 1544.

Portolan charts were locally superb and globally awkward. Ptolemaic maps were learned and not made for compass steering. Mercator tried to give navigators a sheet on which direction did not have to be constantly recomputed as a curve.

Gerard de Kremer, born 1512 in Rupelmonde, trained at Louvain, instrument-maker, engraver, and cosmographer. In 1569 he was in Duisburg, not in a ship’s cabin. Sailors were the intended users, not the makers.

Gerardus Mercator (Gerard de Kremer) · Abraham Ortelius (contemporary, different project)

A wall-sized engraved world map that keeps angles locally true so that a constant compass course (a rhumb, or loxodrome) appears straight. Areas and distances distort, more and more toward the poles.

A projection that stretches meridians toward the poles. Mercator described the use more clearly than the construction. The later analytic form is not what 1569’s readers held in their hands.

The hinge is the 1569 sheet itself: a claim that a particular distortion is the right distortion for a particular task.

A workshop in Duisburg. The map’s geography is the world as European compilation then had it: Atlantic, Indian Ocean, incomplete Pacific, invented or guessed polar zones. 1569, as printed on the map. It is a publication year, not a voyage year.

1569 · Duisburg, Duchy of Cleves

He knew rhumbs were the sailor’s practical path, not great circles. He knew his map was for steering, not for comparing the true size of continents.

How completely later schoolrooms would treat his projection as 'the' world. How badly Greenland and high-latitude empires would look oversized. GPS, aviation great-circle routes, or the political arguments of the twentieth century about map justice.

Mercator world map of 1569

Original impressions are rare museum objects. Later copies and facsimiles circulate. This project does not pretend to display the copperplate. It describes the surviving map.

The object survives.

The 1569 map is the first record of this projection in print.

Adoption was not instant. Wright’s mathematical treatment (1599) and later tables made it more usable. It became the default nautical and then classroom image of the world.

People say Mercator 'drew the world wrong.' He drew it for a job. The later crime, if there is one, is using a sailors’ tool as a political picture of who is large.

The projection’s later cultural life is not evidence that 1569 hid a philosophy of empire in a formula. Motive and later use are different questions.

Does not prove that 69 favors maps, or that Mercator caused later colonial cartography in a single act.

It entered the test because a dated object solves a precise problem of direction, the same problem 1269 had posed with a stone.

How do you make a round world steerable on a flat page?

1. 1. Gerardus Mercator. Nova et Aucta Orbis Terrae Descriptio ad Usum Navigantium Emendate Accommodata. Duisburg, 1569.
2. 2. Edward Wright. Certaine Errors in Navigation. London, 1599. Mathematical treatment of the projection Mercator had used.

independent first · hard