1569 Flemish cartographer Gerardus Mercator 594) published an important map of the world in 1569. The map was based on the Mercator projection, which combines equally spaced longitude lines with latitude lines that become wider apart, the farther away from the Equator. Instead of having to take compass readings again and again to stay on track, the Mercator projection allowed seafarers to plot their course using straight lines and led to accurate navigational charts. Although the Mercator projection distorts the size of lands near the Poles, it has been used in maps ever since.
In 1570, fast on the heels of Mercator's world map, his fellow Flemish cartographer Abraham Ortelius (1527-1598) published Theatrum Orbis Terrarum, which is considered the first modern atlas. He appended a list of sources acknowledging the work of the cartographers, including Mercator, from whom he had drawn for his atlas.