At the invitation of the College of Earth and Environmental Sciences of Lanzhou University, Prof. Tang Guoan from the College of Geosciences of Nanjing Normal University gave a lecture entitled "Digital Geomorphology Methods Based on DEM" at Lanzhou University on February 18, which was hosted by Prof. Jie Yaowen and listened to by more than 150 students and teachers offline and online.

Professor Tang Guoan first proposed the main problems to be solved in the current digital geomorphology representation, then elaborated the analysis methods to effectively describe the digital geomorphology features and the related achievements of intelligent geomorphology classification and cartographic representation. Finally, he introduced the progress of the Deep-time Digital Earth (DDE) big science program, and gave an in-depth analysis of how to improve the resolution of geomorphology classification results, establish a reasonable and unified global geomorphology classification system, and reduce the uncertainty brought by the classification methods. He also introduced a series of the latest achievements of the group in terms of the classification system, classification methods, classification models, and classification results.

The report of Prof. Tang Guoan was very in-depth and informative, which showed the cutting-edge research progress of geomorphology methods in China to the participating teachers and students. After the meeting, Prof. Tang Guoan had a lively discussion with the participating teachers and students. Prof. Gou Xiaohua, Dean of the College of Earth and Environmental Sciences, Prof. Guan Qingyu, vice Deans, and Prof. Geng Haopeng also listened to the whole report. Through this exchange, the cooperation between Nanjing Normal University and Lanzhou University in the discipline of geography was further strengthened.