The plate carrée projection is a map projection in which the horizontal coordinate is the longitude and the vertical coordinate is the latitude. The name derives from the French for "flat square". The plate carrée is a special case of the equirectangular projection, which has been in use since the earliest days of spherical cartography: the Roman mathematician Ptolemy attributed its invention to Marinus of Tyre, in around AD 100. This composite satellite image, titled "Blue Marble", was produced by NASA and shows Earth's land surface, shallow water and shaded topography.Photograph credit: NASA