LiDAR scanning of Coastal Cliffs in Denmark and Greenland with the Apple iPhone 12 Pro

Traditionally, topographic surveying in Earth sciences requires high financial investments, elaborate logistics, tedious training of staff and extensive data processing. Recently, the structure-from-motion (SfM) technique already reduced the costs for obtaining a high-resolution dataset of the Earth surface considerably. Nevertheless, costs and complexity associated with topographic surveying are still high. Here, we test the novel LiDAR sensors build in the Apple Inc. iPad Pro 2020/21 and iPhone 12 Pro by comparing the results to a state-of-the-art SfM point cloud from a coastal cliff in Denmark and Greenland. We use the EveryPoint App to collect LiDAR point clouds and optical images with the iPhone LiDAR sensor and camera simultaneously. Processing of the images and combining the LiDAR with the SfM point clouds is performed on servers from EveryPoint. The LiDAR sensors create accurate high-resolution models of objects with a side length > 10 cm up to several hundreds of meters with an accuracy of +/- one cm. The range of the LiDAR sensor is limited to approximately 5 m. Combining mid-range photogrammetry methods with the close-range LiDAR measurements extends the range considerably overcoming the limitations of the LiDAR sensor. Merging the capabilities of a LiDAR sensor an RGB camera in one mobile device brings together the best of both worlds for the 3D reconstruction of surfaces. Overall, the versatility in handling outweighs the range limitations, making the Apple LiDAR device a cost-effective alternative to established techniques in remote sensing with possible fields of application for a wide range of geo-scientific areas, citizen science and teaching.