Combination of GPR, Mobile Mapping LiDAR and UAV‐SfM for Generating a Thorough Site Investigation of the Late‐Medieval Church Ruin of Gotthardsberg (Bavaria, Germany)

ABSTRACT

The application of geophysical surveys—mainly ground‐penetrating radar (GPR)—to map buried remains of monasteries and churches has been well established for decades because these methods provide valuable information on subsurface stone constructions. In recent years, 3‐D‐mapping technologies such as terrestrial laser scanners (TLS), mobile‐mapping systems and unmanned aerial vehicles (UAVs) have become more affordable. These methods can complement traditional geophysical surveys, yet the benefits of combining both data sources are still often underestimated in research projects. In this contribution, we present an integrated workflow that merges GPR data with a surveyed 3‐D model of a church ruin in northwestern Bavaria (Germany). The aim is to illustrate how both methods can reinforce each other to further improve the interpretation of medieval monastic sites. Furthermore, we generated a 3D visualization of the geophysical anomalies and embedded it into the point cloud. This enhances the perception of the interaction between upstanding and subsurface features, which is especially helpful on difficult terrain. Such three‐dimensional interpretation attempts are still rarely exploited; they are usually applied only as semiautomated interpretation methods without integration with other data sources. Beyond the archaeological analysis of the site's development, we address several methodological questions concerning the advantages and disadvantages of different remote‐sensing techniques for mapping historic buildings. We also present a statistical evaluation of the accuracy of various UAV models and the mobile mapping laser scanner used in the study.