Celebrating thirty years of virtual outcrops: status and perspectives

Thirty years ago, scientists from the Technical University of Denmark and University of Bergen published 3D outcrop acquisition and processing methods for large-scale vertical cliff sections in Greenland (Dueholm & Olsen, 1993), thus laying out a pathway to today’s state-of-the-art in high resolution virtual outcrop modelling. Although the photogrammetric methods employed were based on film cameras and early digital processing, the authors successfully created stereoscopic outcrop models that could be used for accurate measurement of cross sections, channel bodies, and derived parameters such as net-to-gross ratio. Fast forward to today, and virtual outcrop modelling has evolved rapidly, spanning early work using laser scanning, integration with hyperspectral imaging, and the full-circle return to photogrammetry. The latter has brought about a paradigm shift in field geoscience, driven by lightweight digital cameras, drone platforms, and powerful computing hardware combined with automated image matching and point cloud generation algorithms. This has empowered geologists and geoscientists to quickly – and at low cost – acquire and process high resolution, accurate 3D models for detailed analysis. Over the last five years, and particularly through the COVID-19 pandemic, virtual outcrop models have been increasingly used for “soft” purposes, in education and training, for introducing a wide range of different geological features and concepts that may be difficult to access in a single field area, or as the basis for integrating a range of geospatial, field and subsurface data. In this contribution we will explore the status and impact of virtual outcrops and offer thoughts on future perspectives.