Heavy rain disasters in recent years may be an indication of the climate change. As it progresses, disastrous heavy rains may increase as well as human damages and material damages caused by them. Under the circumstances, it is important to update data relevant landwater areas. This study concerns positioning data and echo sounder data to map topographies of water areas, and describes data processing flows.

Masaji Watanabe, Emeritus Professor, Specially Appointed Professor (Research), Okayama University, is active in research fields of applied mathematics. Those include a study on topographic surfaces of water areas. His recent activities include joint studies on measurement and analysis of underwater topography with Mr. Satoshi Iwakami, Mr. Masahiko Tamega, Mr. Masahide Sanada, Mr. Michiaki Mohri, Mr. Yoshitaka Iwakami, Mr. Naoki Okamoto, Mr. Eishi Mitsui (Earth Rise Company, Inc., Okayama, Japan), Associate Professor Ryosuke Akoh (Faculty of Environmental, Life, Natural Science and Technology, Okayama University), and Dr. Shuji Jimbo (Visiting Researcher, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan).