The Geospatial Information Authority of Japan (GSI) is the national surveying and mapping organization. It produces Japan's fundamental geospatial data — topographic maps, elevation models, aerial photography, and administrative and reference layers — and delivers them through GSI Maps and the widely used GSI Tiles.
GSI Tiles provide a free, well-maintained set of base map and thematic raster/vector tiles that are popular for web mapping of Japan. The agency's data underpins national mapping and is straightforward to bring into a GIS as background layers.
