1. Retired, 13510 Flowerfield Dr., Potomac, MD 20854; formerly, Chief Technical Officer, Spatial Reference System Div., NGS, 1315 East-West Highway, Silver Spring, MD 20910.
2. Professor, Dept. of Civil Engineering, National Taiwan Univ., No. 1, Sect. 4, Roosevelt Rd., Taipei 10617, Taiwan (corresponding author). ORCID: .
3. Ph.D. Candidate, Dept. of Civil Engineering, National Taiwan Univ., No. 1, Sect. 4, Roosevelt Rd., Taipei 10617, Taiwan.