7 Seeing the True Shape of Earth’s Surface: Applications of Airborne and Terrestrial LiDAR in the Geosciences

Sunday, 31 October 2010
8:00 AM - 12:00 PM
Room 502

MODELING AND ANALYSIS OF LANDSCAPE EVOLUTION AT MULTIPLE SCALES USING AIRBORNE, TERRESTRIAL, AND LABORATORY LASER SCANNING

Paper number: 7-14
Program: Technical Sessions
Time: 11:05 AM – 11:20 AM

Authors

Abstract

Repeated lidar surveys that generate a time series of point cloud data provide an opportunity to transition from traditional, static representations of topography to terrain abstraction as a 3D dynamic layer. A framework for landscape evolution analysis has been proposed using a terrain dynamics metrics that captures spatial and temporal variability of elevation surface. A raster based approach introduced the concepts of core and envelope surfaces, time of elevation min/max maps and per cell regression analysis of elevation change trends. Representation of terrain dynamics using a space-time trivariate function z=f(x,y,t) further extends this concept by using voxel models to extract evolution of contours as isosurfaces. For example, shoreline evolution is approximated by isosurfaces representing mean high water elevation and a vector of the fastest elevation change in space-time domain is mapped using spatio-temporal gradients.

Current 3D laser scanning technologies span a wide range of spatial scales, from regional airborne lidar mapping and terrestrial lidar field surveys to laboratory systems utilizing indoor 3D scanners. Several case studies are presented to illustrate the proposed terrain evolution analysis at different spatial and temporal scales: (a) study of a dynamic coastal region using multiyear airborne lidar surveys, where the change is driven by wind sand transport, wave induced beach erosion and human intervention such as beach nourishment and dune stabilization; (b) analysis of land surface elevation change due to soil erosion/deposition and vegetation growth using time series of terrestrial lidar scans of agricultural field; (c) investigation of terrain change impacts on water flow and erosion using flexible, 3D laboratory models that are modified by hand and the impact of changes is analyzed and projected back onto the model using a Tangible Geospatial Modeling System coupled with GRASS GIS.