This map of the Netherlands coast is the work of Prussian cartographer Franz Ludwig Güssefeld (1744-1807). It was drawn based on the calculations of the renowned Dutch mathematician Willebrord Snellius (1580-1626), a professor of mathematics at the University of Leiden, who conceived the idea of measuring the earth using triangulation. Snellius’s discoveries helped to determine the radius of the earth as well as led to more accurate ways of measuring the distance between two cities.