Credits and thanks

This site is a dwg7 activity. It is not an official project of OpenAerialMap (OAM) or HOT. We tried the new OAM and show its image on a map. We want to say thank you, and to give correct credit.

このサイトは dwg7 の活動であり、OAM や HOT の公式なものではありません。新しい OAM を試し、その画像を地図にしています。感謝と、正確な出典の表示をここに書きます。

The image

Title: Waterloo, Sierra Leone
Provider: HOT (Humanitarian OpenStreetMap Team). OAM lists HOT as provider and as the licensor.
Acquired: 2026-02-07 to 2026-06-03 (dates in the OAM metadata)
Aircraft and size: DJI Mini 5 Pro (a small drone). About 5 cm per pixel. The source file is about 4.7 GB.
Added to OAM: 2026-09-19
License: CC BY-SA 4.0 (legal text). This is the value in the OAM metadata and in the OAM STAC record.
Original page: New OAM (ID 6aae46379ed4c3b5f2d117f9) · STAC record · uMap that uses this image

What we changed (license note)

We changed the format. The original is one large GeoTIFF. We cut it into map tiles (WebP, 512 px, zoom 10 to 21, resampled with the Lanczos method) and packed them into a PMTiles file. We also tested the PMTiles file that OAM makes itself (zoom 10 to 20, 256 px). The pixels were resampled; nothing was added or painted over.

The tiles we serve are also licensed under CC BY-SA 4.0, the same as the source image. If you reuse them, please give the credit above and keep the same license.

Overture Maps data

The building and road lines come from Overture Maps Foundation, through tiles already served on stars.optgeo.org. We follow the Overture attribution page.

Buildings (ODbL): © OpenStreetMap contributors; also Esri Community Maps contributors (CC BY 4.0), Microsoft Global ML Building Footprints (ODbL), Google Open Buildings (CC BY 4.0), and other sources listed by Overture.
Transportation / roads (ODbL): © OpenStreetMap contributors; data from TomTom is also listed by Overture.
Credit line we show on the map: © Overture Maps Foundation, © OpenStreetMap contributors.

We did not check which of these sources actually appear in Waterloo. We list the sources that Overture lists for each theme.

OpenStreetMap data is available under the Open Database License.

Thank you

We say thank you with specific things.

To the people who flew and processed this survey. The record says the flights ran from February to June 2026 with a small DJI Mini 5 Pro, and the result is sharp at about 5 cm. That is a lot of careful flying and processing. The public records do not name the pilots, so we do not name anyone. The OAM record gives Ping Yee of HOT as the contact.
To HOT, for providing the image and for choosing an open license (CC BY-SA 4.0), so that anyone may use it, including us.
To the people who built the new OAM. The image, its STAC record and the tile-pack API are open. We could try the PMTiles feature without a sign-in, in the same way any user can. A short, clear help text on the API page also helped us. Our trial notes are in docs/oam-pmtiles.md; we wrote them as a thank-you and a report, not as criticism.
To OpenStreetMap contributors and Overture Maps contributors, for building and sharing the building and road data that we put on top of the image.
To the open-source projects we use: MapLibre GL JS, PMTiles (Protomaps), GDAL, and Martin.

日本語の補足：撮影者の個人名は公開情報で確認できないため書いていません。OAM のメタデータにある連絡先として Ping Yee さん（HOT）のお名前のみ、公開されている範囲で記しました。

No marks or notes on this map point to people or houses. The map only shows the image.

Source code and notes: github.com/dwg7/waterloo (UNopenGIS/7 #1023).