Among the greatest dangers facing a modern mariner is the use of obsolete maps. Albion has been mapped for many centuries at least, but many of the old maps contain significant inaccuracies. This is primarily attributable to two main causes.
The Shape of the World
It is only in the last century that the greatest minds in Albion have determined that the world is not flat, as it appears, but actually spherical. Obviously, rendering a sphere as a flat, two-dimensional drawing introduces errors. The Bowerstone Maritime Academy has on permanent display a 500-year-old map of Albion, which shows Bowerstone Bay as much smaller than its actual size. Further, the islands containing Knothole Glade and Hook Coast are shown due west of the main landmass, whereas in fact they lie almost directly northwest of Bowerstone and its environs.
Using a sextant, navigators can calculate their position with far greater precision than was possible with earlier instruments. The remarkable sextant likewise allows cartographers to plot land features with extraordinary accuracy. Using a modern sextant, a skilled cartographer can achieve astounding precision, in some cases to within a radius as small as three miles!