Map of Ireland (1790) – Detail with Overlay

David Rumsey’s Historical Map Collection includes a Map of the Kingdom of Ireland by J. Rocque, printed for Robt. Sayer, opposite Fetter Lane, Fleet Street, c. 1790.

Rumsey digitized the original map by scanning it with high resolution digital cameras; the digital image of the historical map was then transformed in a process called “georeferencing”, which made it display in its correct geographical spaces in Google Maps. Georeferencing is done using a GIS program, which takes points on the old maps (cities, coast lines, rivers, streets) and connects them to the same points on a modern satellite map image or a modern street map or a modern map showing boundaries of countries and states. The GIS program then takes all these points (as many as 200 are made for very large maps) and uses them to recreate the digital image so it will fit into its modern geographical space.

View Roque’s map of Ireland.

We have extracted a detail from Rumsey’s composition in the vicinity of the Limerick-Tipperary border near Galbally, where the Allen family was located around this time. View this detail with an overlay from Google Maps.