Area of Nishinoshima Island increased by more than 1 square kilometer
Geospatial Information Authority of Japan (GSI), with cooperation from the Ministry of Defense and Ogasawara Village, carried out aerial photography over Nishinoshima Island by an Unmanned Aerial Vehicle (UAV) on July 4th, created Digital Elevation Models by analyzing the aerial photographs that were taken, and measured the area, highest elevation and volume. As a result, it can be seen that the area of Nishinoshima Island has increased by 1.08 square kilometers in comparison with before the eruption (November 2013), reaching 1.30 square kilometers at the time of photography; the highest elevation point on Nishinoshima Island is approximately 74m; the volume is approximately 22.2 million cubic meters; and the eruption of lava is still not showing signs of weakening.
GSI has published on the Internet the aerial photographs, the Digital Elevation Model of a 1-meter mesh that is useful for research of volcanic topography, and 3D maps and topographic interpretation map of Nishinoshima Island.
Based on the experience of photography with the UAV last time (on March 22nd), numerical measurement accuracy has been improved in photography this time by seeking accurate positions of UAV departure and landing points locally with GNSS observation and correcting the location information of UAV.