Bench Marks of Change: Heritage Survival, Loss, and the Reading of Landscape

Ordnance Survey (OS) bench marks are small, chiselled survey marks, typically composed of a horizontal line or indentation above an upward-pointing arrow. Used by the OS to measure height during the nineteenth and twentieth centuries, they shaped topographic knowledge in Ireland, Great Britain and beyond. Despite their ubiquity, they have received little scholarly attention, with recording projects emphasising surviving examples while overlooking the potential significance of those obscured or destroyed. ‘Locating Bench Marks, Preserving Heritage’ is a digital participatory project that uses the location of bench marks as shown on early OS maps of County Limerick to guide present day field observations recording their survival and loss. Combining participatory methods, archival cartography and GIS, it produces a place-based digital photographic archive of heritage presence and absence, revealing a striking pattern of loss, with over 90% of bench marks no longer extant or visible. The project demonstrates the value of integrating spatial technologies with academic and public co-creation, the latter essential in drawing on local knowledge. Further, it illustrates how one form of heritage can serve as an indicator of wider transformations in built and natural environments, reframing heritage loss not as absence alone but as new evidence of landscape change.