Ian Sherry explains how the island of Ireland was successfully mapped
We started by marking trees and stones on the way out, we followed them back on the way in. Then, when we went further afield, it was the permanency of the North Star and the movement of the Sun that guided our path.
Potelemy (a Greek who lived in Egypt during the first century), knew that the earth was a sphere, and on top of that, had the mathematical ability to project his known world on to a flat surface and construct a co-ordinated map.
By 1609 the Gaels of Donegal were savvy enough to know that maps give military intelligence, and beheaded Richard Bartlett (the Queen’s mapmaker) to forestall a knowledge of their land. But only for a short time because, after the Cromwellian wars, the English natural philosopher William Petty was put in charge of one thousand soldiers to document confiscated farms.