Digitising the Abstracts of principal lines of spirit levelling in Ireland (Principal Investigator - Nowlan Digitisation Grants scheme, Royal Irish Academy)

Catherine Porter will be continuing her work on “Digitising the Abstracts of principal lines of spirit levelling in Ireland”. In the late 1830s, the Ordnance Survey (OS) began a pioneering national effort to measure height across Ireland. Each measurement point was marked on the landscape with a distinctive cut, known as a “crow’s foot,” carved into stone structures such as bridges, walls, and churches. Despite their importance, Ireland has no comprehensive digital record of these early benchmarks. The original list of sites from the first principal levelling survives in a rare 1855 OS publication, which records detailed information for each measurement point, including descriptive location, altitude, and associated OS map sheet and the proposed project will involve conservation safe photography, OCR, and the creation of a structured dataset of bench mark entries.