Digital Preservation and Augmented Reality for Historical Surveying Instruments: A Photogrammetric Approach to Cultural Heritage Documentation
Abstract. Historical surveying instruments represent invaluable cultural heritage artifacts that embody centuries of scientific and technological advancement in geodesy and cartography. However, their inherent fragility and limited accessibility restrict their educational potential and preservation. This study proposes an integrated digital preservation methodology for the Cartographic Sciences Museum at the Federal University of Pernambuco (UFPE), combining low-cost smartphone photogrammetry, three-dimensional reconstruction, geometric optimization, and augmented reality (AR) visualization. A Structure-from-Motion (SfM) workflow processed 303 smartphone images (Xiaomi Poco F5 Pro) with systematic multi-angular capture and controlled overlap (30-60%). A three-chunk processing strategy in Agisoft Metashape optimized computational efficiency while maintaining geometric consistency. Post-processing in Blender reduced polygon complexity by 90% while preserving critical morphological features. Metric validation achieved root mean square error (RMSE) of 0.42 cm, demonstrating geometric fidelity adequate for heritage documentation. Integration into an AR application (Unity/Vuforia) enabled interactive mobile visualization of digitized artifacts. This methodology democratizes access to the UFPE collection for academic research and public engagement, enabling students, researchers, and the general public to explore historical geodetic instruments interactively. Results demonstrate that accessible, low-cost technologies can achieve quality comparable to conventional surveying methods while advancing digital heritage preservation and science communication.