Geospatial Information Authority of Japan
Created by editing GSI Tiles (Digital Topographic Map)
The bathymetric contours are derived from those contained within the GEBCO Digital Atlas, published by the BODC on bahalf of IOC and IHO (2003) (http://www.gebco.net)
Shoreline data is derived from: United States. National Imagery and Mapping Agency. "Vector Map Level 0 (VMAP0)." Bethesda, MD: Denver, CO: The Agency; USGS Information Services, 1997.