Underwater Archaeology in Archives: Georeferencing and Spatial Validation of Archival Documentation at the Medieval Harbour of Puck (Poland)

This study presents a workflow for georeferencing legacy underwater archaeological plans from the medieval harbour in Puck (Poland) and integrating them into GIS. Archival drawings from the 1980s and 1990s, based on different local grids, were digitised, spatially reconstructed and validated against multibeam echosounder (MBES) data with RTK positioning. The procedure unified ca. 40 years of documentation, identified spatial offsets in earlier plans, mapped 5.96 ha of documented remains, and revealed a destroyed corridor and substantial erosion of organic deposits. The workflow demonstrates how legacy analogue documentation can be transformed into analytically reliable archaeometric datasets.