The airborne light detection and ranging (LiDAR) technology provides highly accurate measurements of objects on the Earth’s surface. In contrast to optical remote-sensing technology, a LiDAR remote-sensing system derives voluminous three-dimensional point measurements of the Earth’s surface. The major challenge for the utilization of the airborne LiDAR

technology is to develop appropriate methods to extract the desired features such as topography, vegetation, and buildings from LiDAR measurements. Numerous methods on feature extraction from LiDAR measurements and the applications of LiDAR technology to measuring and monitoring the Earth’s surface processes have been developed in the past 20 years. To appropriately use the LiDAR data, it is necessary to understand the characteristics of airborne LiDAR technology and feature extraction algorithms related to processing LiDAR data. This chapter briey introduces the airborne LiDAR technology, presents the ltering algorithms for separating ground and nonground LiDAR points and discusses the issues related to ltering processes, presents a framework to construct building models from LiDAR measurements, and describes the applications of LiDAR technology on mapping vegetation.