What Products Can be Generated from LIDAR?
LIDAR provides a cost-effective means to collect digital information about the Earth's surface. Using LIDAR, we can obtain several "layers" of information from the landscape through a series of LIDAR returns. The first return of information to a LIDAR sensor would, for example, be associated with the highest features in the landscape (typically treetops, tops of buildings, etc.). Following data returns would be associated with understory vegetation below the initial tree or vegetation canopy. The final return would be associated with the bare earth. This is how LIDAR is used to generate DEMs.
LIDAR is used to generate elevation maps and identify other landscape characteristics, including slope and aspect (through a TIN), as well as volume. A variety of products can be developed using LIDAR data, including highly accurate contours that can be used to generate Special Flood Hazard Areas (SFHA) and Flood Insurance Rate Maps (FRIMs). Flood risk assessments are increasingly being conducted using LIDAR. Vegetation and forestry inventory assessments are conducted with LIDAR. Urban areas use LIDAR to generate three-dimensional maps showing structures and landforms. These data support a variety of planning needs (i.e., viewsheds, emergency management plans, storm water runoff management plans, etc.).
Samples of LiDAR-derived Bare Earth and Vegetation Models for a Plot in Texas
Images courtesy of UT Center for Space Research
In the above example, LiDAR was used to create two models that looked at the above ground vegetation and the topography below ground. Both models are useful in understanding the biologic forces of the region. When these products are combined with other remote sensing products, it helps paint a better picture of the ecological working of an area of interest.