Assessing LiDAR Elevation Data for KDOT Applications.

摘要

LiDAR-based elevation surveys are a cost-effective means for mapping topography over large areas. LiDAR surveys use an airplane-mounted or ground-based laser radar unit to scan terrain. Post-processing techniques are applied to remove vegetation and reveal the bare-earth elevations. In recent years, LiDAR hardware and processing technologies have improved greatly. LiDAR surveys are now cost-competitive with traditional aerial topographic surveys and offer the capability to produce very high resolutions (potentially over 50 points per m2 with <10 cm vertical accuracy for airborne systems). LiDAR survey data may not replace traditional ground-based survey for applications that require centimeter or sub-centimeter accuracy, but the data available from these surveys may be perfect for many engineering applications. One such application is hydraulic modeling with HEC-RAS. Hydraulic models, used for flood-plain mapping and the evaluation of bridge backwater effects, require detailed elevation maps for the stream channel and floodplain. These data are difficult to obtain using traditional aerial survey techniques due to riparian vegetation that obstructs the view of the stream channel. Another potential application for LiDAR data is earthwork calculations (cut/fill analysis) for preliminary route planning purposes. Because LiDAR surveys are fairly new, the applications and limitations of these data have not been explored. This report summarizes an extensive literature review of LiDAR applications.