Abstract

Yosemite Valley experiences numerous rockfalls each year, with over 600 rockfall events documented since 1850. However, monitoring rockfall activity has proved challenging without high-resolution "basemap" imagery of the Valley walls. The Yosemite Extreme Panoramic Imaging Project, a partnership between the National Park Service and xRez Studio, has created an unprecedented image of Yosemite Valley's walls by utilizing gigapixel panoramic photography, LiDAR-based digital terrain modeling, and three-dimensional computer rendering. Photographic capture was accomplished by 20 separate teams shooting from key overlapping locations throughout Yosemite Valley. The shots were taken simultaneously in order to ensure uniform lighting, with each team taking over 500 overlapping shots from each vantage point. Each team's shots were then assembled into 20 gigapixel panoramas. In addition, all 20 gigapixel panoramas were projected onto a 1 meter resolution digital terrain model in three-dimensional rendering software, unifying Yosemite Valley's walls into a vertical orthographic view. The resulting image reveals the geologic complexity of Yosemite Valley in high resolution and represents one of the world's largest photographic captures of a single area. Several rockfalls have already occurred since image capture, and repeat photography of these areas clearly delineates rockfall source areas and failure dynamics. Thus, the imagery has already proven to be a valuable tool for monitoring and understanding rockfall in Yosemite Valley. It also sets a new benchmark for the quality of information a photographic image, enabled with powerful new imaging technology, can provide for the earth sciences.