Early statistical modelling of latent quantities: The history of distance measurement by triangulation

Measurement of long distances in astronomy and geodesy has an interesting history involving the inception of several statistical concepts, such as least absolute deviations, least squares, maximum likelihood, and robustness. Geographical maps are models of locations on Earth. Maps at a small scale rely on some map projection method and knowledge of latitude and longitude. Maps at a larger scale became to be be based on angle measurement in triangulation networks, without information on latitude or longitude. Absolute size of the Earth was estimated by measuring amplitude and length of a meridian arc. Map making projects of Mercator, the Blaeu family, the Cassini family, and Ino are discussed, as well as theoretical contributions of Frisius, Snellius, Galilei, and Gauss.