Visual Detection and Interpretation of Cultural Remnants on the Königstuhl Hillside in Heidelberg Using Airborne and Terrestrial LiDAR Data

Abstract

LiDAR-based data acquisition, also referred to as laser scanning (LS), is an exceedingly used procedure for investigating site-specific details and spatial context. The main product of LiDAR scanning is digital elevation models (DEMs) derived from recorded 3D point clouds. Two major outcomes of DEMs are digital terrain models (DTM) of the bare earth and digital surface models (DSM) with canopy details. For detection and management of information from the past, especially, the DTM reveals important information for understanding, investigating, and managing sites and landscapes of cultural heritage interest.

In this case study, the advantages and disadvantages between airborne and terrestrial LiDAR DTM data are assessed. The investigations resulted in a differentiated perspective on scale of view and concluded that highest resolution is not always the best practice for visual detection of cultural heritage monuments in areas with complex canopy details, such as in dense vegetation. Because dense vegetation can disturb and distort terrain and surface segmentation to such a degree, the information retrieved might be more difficult to understand compared to visualization with less canopy details. Thus, the best practice is presently established in a combination of the two approaches. Minor details are lost in the ALS data, but large-scale context elude us by only using TLS data.

Our study revealed both major and minor details of infrastructure in the landscape from the eighteenth and nineteenth century. Many of the structures and details in the landscape have not been described or documented before and provide new understanding on cultural activity on the Königstuhl hillside in Heidelberg. Hereby especially two cellar structures were of particular interest to the investigations carried out.