GSI Maps

GSI Maps (Chiriin Chizu) is the web map of the Geospatial Information Authority of Japan (GSI), Japan's national mapping agency. It publishes the geospatial information GSI maintains about Japan, including topographic maps, aerial photographs by era, elevation, landform classification and disaster information, and anyone can view it free of charge in a PC or smartphone browser. GSI promotes it for school geography and disaster education and for disaster-management work in national and local government. Users can check land-condition, landform and active-fault maps to understand an area's hazard risk before a disaster. After a disaster, they can view the emergency aerial photographs and damage maps that GSI publishes.

Satellite layers can be switched on over the aerial and cartographic base maps. They include a nationwide Landsat 8 mosaic, a global mosaic built from MODIS 8-day composites, and dated imagery layers that include Axelspace GRUS satellite images. GSI also produces interferometric SAR (InSAR) results from JAXA's ALOS, ALOS-2 and ALOS-4 data, showing crustal deformation caused by earthquakes and volcanic activity.

The tools cover elevation, address and coordinate look-up, distance and area measurement, terrain cross-sections, side-by-side comparison of maps and photographs, 3D views, drawing with KML/GeoJSON files, printing, and sharing by link or QR code. The underlying map data are distributed as GSI Tiles (XYZ map tiles), which other websites and apps can load in real time with attribution only. GSI publishes the source code of GSI Maps on GitHub under a BSD-2 licence.