GSI Emergency-Response Aerial Imagery, as Cloud-Optimized GeoTIFFs

Cloud-Optimized GeoTIFFs (COGs) reassembled from Japan's Geospatial Information Authority (GSI, 国土地理院) disaster-response aerial imagery -- the _do / _do_sokuho (正射画像 / 正射画像速報, "emergency ortho") tile layers GSI publishes during and after a disaster response, before they're folded into GSI's regular map products.

Published by the UN Smart Maps Group. Generated by optgeo/cogenerate, an open pipeline that reassembles GSI's XYZ tiles into standard, cloud-native GeoTIFFs -- see that repository for the code, and for exactly how each file was produced.

What's in this dataset

One COG per GSI emergency-ortho layer. Filenames follow GSI's own layer IDs directly (<disaster-and-area-id>_<capture-date>do[_sokuho].tif -- e.g. 20260729kumamoto_yatsushiro_0729do_sokuho.tif is GSI's own layer ID 20260729kumamoto_yatsushiro_0729do_sokuho, captured 2026-07-29), so any given file's provenance is traceable straight back to GSI's own tile server (https://cyberjapandata.gsi.go.jp/xyz/<layer id>/{z}/{x}/{y}.png) and to GSI's own catalog page (https://maps.gsi.go.jp/development/ichiran.html, search the layer ID). This dataset grows over time as new disasters happen and get processed -- this file won't always list every layer present; browse this product's file listing, or the pipeline repository's static STAC catalog once available, for the current set.

• Format: Cloud-Optimized GeoTIFF, RGBA, EPSG:3857 (Web Mercator -- matching GSI's own native tile grid; reproject if you need a different CRS for measurement/survey work).
• Resolution: native GSI z18 tile resolution (~0.6m/px at this latitude), COG overviews included.
• NODATA: transparent (alpha=0) both outside the surveyed coverage polygon and for any pixels GSI's own source imagery encoded as solid black rather than transparency. No pixels are backfilled or synthesized -- transparent means "no data," not "photographed as black."

Data source, license, and attribution

Source imagery: Geospatial Information Authority of Japan (国土地理院), via GSI's own disaster-response tile service. Attribution is required when using this data -- credit "国土地理院" ("Geospatial Information Authority of Japan") with a link to https://maps.gsi.go.jp/development/ichiran.html. Check that page's entry for the specific layer you're using (search by the filename, minus .tif) for any additional terms beyond the blanket attribution requirement.

GSI's own remark on this class of layer, present on essentially every _do/_do_sokuho entry checked so far (translated): "Because this is automatically processed from photographs, some areas may show distortion or discontinuities around structures, and cloud cover may obscure the ground in places." Treat these COGs as disaster-response imagery, not surveyed base mapping -- accuracy and completeness follow whatever GSI's own source imagery had at capture time.

Provisional attribution note: disaster-response layers can appear on GSI's live tile server before GSI's own ichiran.html catalog page lists them (observed directly during this pipeline's development -- see the cogenerate repo's DECISIONS.md D9). Where that's the case for a given file, its attribution/remarks couldn't be cross-checked against ichiran.html as of that file's generation date -- re-check before relying on it for anything beyond casual use.

This dataset's own packaging (file layout, COG generation) is CC0-1.0 (see optgeo/cogenerate's LICENSE); that does not waive GSI's own attribution requirement on the underlying imagery, which is a condition of GSI's data terms, not this project's choice.

Feedback / issues

File an issue at https://github.com/optgeo/cogenerate/issues, or see that repository's README.md for other contact paths.