Abstract
Up to the present, aerial photography had been widely used for making terrain maps. The Laser Profiler, on the other hand, has been paid attention to, recently. This method is that laser scanner mounted on aircraft irradiates laser pulse in order to scan terrain surface, and measures the distance from ground by calculating the time lag between irradiation of a pulse to the ground and its returning to aircraft. This method enables us to record 3D digital topographical information.
With the laser profiling, we succeeded in getting the topographical information of Usu Volcano, which erupted in March of 2000. Comparing that information with the topographic data taken before its eruption made it possible to calculate the change of ground levels, occurred by its eruption.
It has been confirmed that the laser profiling has remarkable advantages like the followings. Because the data is directly recorded in digital, the process and period for making the data can be less than using aerial photography. And also those data make it easier to proceed GIS analysis.
However, this method is affected by the wooding condition in case of recording the data of ground level, and also has no certain way to know the object shown by recorded data. These remained problems have to be tested and verified from now on.
