1. Ph.D. Candidate, Dept. of Earth and Atmospheric Sciences, National Center for Airborne Laser Mapping, Univ. of Houston, Houston, TX 77204 (corresponding author).
2. Associate Professor, Dept. of Earth and Atmospheric Sciences, National Center for Airborne Laser Mapping, Univ. of Houston, Houston, TX 77204.
3. Associate Professor, College of Civil Engineering and Architecture, Beijing Univ. of Technology, Beijing 100124, China.
4. Ph.D. Candidate, Dept. of Earth and Atmospheric Sciences, National Center for Airborne Laser Mapping, Univ. of Houston, Houston, TX 77204.