Digital elevation data of Nakadake first crater, Aso Volcano, Japan, in March and May 2015

We here present two digital elevation models (DEMs) for the Nakadake first crater, Aso Volcano, Japan (Kazama et al., 2015). The DEMs were created using the software of Agisoft PhotoScan (version: 1.1.5), and synthesized from photographs taken with DJI Phantom 2 Vision FC200 and PENTAX Optio WG-2. Two zip files (1503.zip and 1505.zip) correspond to the DEMs as of March and May 2015, originating from the photo data taken on March 26-27 and May 8, 2015, respectively. In synthesizing the DEMs, the absolute coordinate of the ground surface was fixed by seven ground control points (GCPs) located around the crater; the GCPs' coordinates had been determined with GNSS surveys in advance.

In each zip file (15??.zip), 15??.xyz indicates the raw topographic data, and its each line contains longitude [deg], latitude [deg] and elevation [m]. The DEM resolution is 0.000005 deg (~= 50 cm) for longitude and latitude, and 0.000001 m for elevation. Both 15??.stl and 15??.pdf are the three-dimensional shape of the DEM data, and they can be shown using typical 3D viewers and Adobe Acrobat Reader, respectively. Both 15??.jpg and 15??.kmz are the orthophotographs of the Nakadake crater; in particular, 15??.kmz can be projected to maps using map softwares such as Google Earth Pro.

Note that the DEM coordinate may contain random and/or systematic errors greater than the DEM resolution. According to the PhotoScan software, the coordinate errors of the GCPs were estimated to be (longitude, latitude, elevation) = (0.62, 4.01, 6.87) and (4.27, 3.94, 1.78) meters for 1503.xyz and 1505.xyz, respectively.

Acknowledgments: Aso Volcano Disaster Prevention Council helped us taking photographs at the Nakadake first crater.