Mr. XU Houze, member of the Chinese Academy of Sciences (CAS) and outstanding alumnus of Tongji University, paid a visit to the College of Surveying and Geo-Informatics (CSGI), Tongji University by invitation on the afternoon of May 10th, and gave a high-end presentation on the theme of Reflections on Elevation System. Leaders, faculty members, undergraduates, and graduate students from CSGI attended the presentation.