Early Maps of Ireland
The first maps of Ireland were drawn up based on the charts and pilots (diaries) created by sailors from Greece, Rome and other parts of the Mediterranean. As a result, they weren't very accurate!
As Ireland was visited more often, the maps of the coast improved significantly, and the blank spaces of the land were filled in. This took several centuries, however - the process was slow, with some areas of Connaught badly mapped up into the late Middle Ages.
Early maps were largely drawn up by the military, for either offensive or defensive reasons. They continued to play an important role in the creation of maps (or cartography) up to the end of the nineteenth century.
Ptolemy's Map of Ireland