Is it true that shipping lanes on a Mercator projection map give the impression that the Earth is flat?

Answer

Dear Ersoy

A mercator projection is created by the projection of points on a sphere (the Earth) to a north-south oriented cylinder enclosing this sphere (such as a toilet roll around a ping pong ball). In addition, a scaling correction to higher latitudes is applied, so that the latitudes in the direction of the poles are further apart instead of closer together. That cylinder is then cut and rolled out along the longitudinal axis, as it were. The result is a map of the Earth in mercator projection, eg with the Atlantic Ocean in the middle.

The mercator projection method therefore assumes a spherical Earth and it is therefore impossible to show that the Earth is flat using a mercator projection map. A flat Earth and a Mercator projection are mutually exclusive.

The advantage of the mercator projection method over other projection methods from a sphere to a plane is that it is true to the angle and that a fixed compass heading forms a straight line on the map; hence the advantage for shipping.

A disadvantage of the mercator projection, however, is that surfaces at high latitudes are greatly magnified. Greenland, for example, appears larger than all of Africa, but in reality the area of ​​Greenland is smaller than that of Algeria. You can check this interactively visually on the The True Size Of website. This may not matter much to a sea captain, although he should know that a straight line on such a chart is usually not the shortest connection between two points. For example, for the shortest route from Paris to Vancouver, an air captain does not follow the 49^ON latitude, but he/she flies over Greenland. This can be seen nicely on Google Earth using the ruler between the two locations.

Also for Norfolk-Gibraltar, the route along the latitude (36^ON) is longer than the shortest route north of the Azores.