1. Postdoctoral Research Associate, Spatial Science Laboratory, Texal Agrilife Research, Texas A&M Univ., 1500 Research Plaza, College Station, TX 77843; formerly, Dept. of Civil and Environmental Engineering, Colorado State Univ., Fort Collins, CO 80523 (corresponding author).
2. Associate Professor, Dept. of Civil and Environmental Engineering, Colorado State Univ., Fort Collins, CO 80523.
3. Professor, Dept. of Civil and Environmental Engineering, Colorado State Univ., Fort Collins, CO 80523.
4. Professor and Head, Dept. of Agricultural and Biological Engineering, Purdue Univ., West Lafayette, IN 47907.