New Visualization Techniques to Analyze Ultra-High Resolution Three- and Four-Dimensional Airborne and Tripod LiDAR Point-Cloud Data
Kreylos, O - Institute for Data Analysis and Visualization (IDAV),
University of California, One Shields Avenue, Davis, CA 95616, United States
Bawden, G W - US Geological Survey, 3020 State University Drive East, Modoc Hall Suite 4004, Sacramento, CA 95819, United States
Kellogg, L H - Department of Geology, University of California, One Shields Avenue, Davis, CA 95616, United States
In the context of the UC Davis W. M. Keck Center for Active Visualization in the Earth Sciences (KeckCAVES, http://www.keckcaves.org), we are developing an immersive visualization application to display and interact with very large (billions of points) three- and four-dimensional point-position datasets, such that point groups from repeated airborne and ground based Light Detection And Ranging (LiDAR) surveys can be selected, measured, and analyzed for quality control and land surface change detection. One of the difficulties of analyzing dense 3D and 4D point-cloud data is that there are few software packages that can display and analyze the data at full resolution and in the natural 3D perspective in which it was collected. We developed an octree-based, multiresolution, point-set data representation that allows very large point cloud datasets to be displayed at the frame rates required to create immersion (between 60 Hz and 120 Hz). Data inside an observer's region of interest is shown in full detail, whereas data outside the field of view or far away from the observer is shown at reduced resolution to provide context. Users can navigate LiDAR data sets and accurately select related point groups in two or more point sets by sweeping space using 3D input devices provided by immersive display environments such as CAVEs. Users can then guide the software in deriving positional information from point groups to compute displacements between surveys, or to extract survey measurements. This software runs on UNIX-like operating systems and can be used on laptop or desktop computers, 3D display systems such as Geowalls, and in fully immersive environments such as CAVEs. It is available for download from http://www.keckcaves.org. Examples of the wide range of applications of the software for airborne and Tripod LiDAR (T-LiDAR) include: 1)~visualization of airborne LiDAR data from the southern San Andreas Fault; 2)~quality control assessment of ground based T-LiDAR from the March 2006 Ka~Loko Dam breach on Kauai; and 3)~4D T-LiDAR time-series analysis from the June 2005 Blue Bird Canyon landslide in Laguna Beach, southern California.
UR: http://idav.ucdavis.edu/~okreylos/ResDev/LiDAR
