The Irish coast is forever changing and map makers know this better than most. Down through the centuries cartographers representations of Ireland have transformed from efforts that are barely recognizable to us today – and would have likely been of limited practical use at the time – to our modern maps of incredible accuracy for precision navigation.
While modern maps benefit from a range of technologies like satellite imagery and GPS, the very first map of Ireland was created quite differently. The earliest known map of Ireland dates from around 140 AD and was created from information collected by the Greek cartographer and astronomer Ptolemy.
Amazingly Ptolemy never actually visited Ireland himself but instead gathered a list of place names and their exact location in longitude and latitude based off sea charts and diaries of Greek and Roman sailors. This information was centuries later used to create an approximate map that isn’t too far off the mark as you can see above.
Maps derived from Ptolemy’s descriptions were used until the 15th and 16th century when new maps of Ireland were commissioned, invariably for military purposes.
With the establishment of the Ordnance surveys in the 18th century, maps became even more accurate until we reach the familiar landmass shape we now instantly recognize as Ireland.
Interestingly though, this isn’t the ‘true’ map of Ireland as the islands actual territory is a lot bigger than we think. Our marine territory extends far beyond our coastline encompassing 880,000 km2 and this huge area is more than 10 times our land mass. The map below shows this enormous area.
This map was developed by a joint venture by the Geological Survey of Ireland and the Marine Institute, and it shows Ireland’s current designated Irish Continental Shelf, which is one of the largest seabed territories in Europe. The continental shelf is the extension of a State’s territorial waters, where the natural land extends under the sea to the outer edge of the continental margin beyond 200 nautical miles from the coastline baseline.
For a country famed for being green, we sure have a lot of blue!