wtf is ogn-3d-viewer?

OGN 3D Viewer is a browser application that replays glider flights in three dimensions using data from the Open Glider Network, a community project that tracks glider positions worldwide. You pick an airfield by its code and a date, and the viewer reconstructs the day's flight tracks over 3D terrain. You can then play them back, switch to a cockpit view from inside the glider, or follow along with a chase camera. A head-up display shows heading, altitude, and climb rate as the replay runs. The feature set is broad. The loading screen lets you search for airfields, browse famous gliding sites by continent, import your own flight files (IGC, GPX, KML), or check where gliders are currently airborne. The 3D scene includes satellite terrain, named summits and waypoints as points of interest, a minimap, and visual effects like contrail and bloom on the flight paths. Playback supports speeds from a quarter speed up to 30 times, plus graphs of altitude, speed, and heading. Instruments estimate the glider's attitude and vario readings, and the interface is available in five languages. You can share links with QR codes, export images, and use the app offline as a progressive web app. Under the hood, the project is a client-side single-page application written in TypeScript and bundled with Bun. There is no backend server, the app runs entirely in the browser. It uses deck.gl for 3D rendering, pulls flight logs from the OGN FlightBook API, fetches elevation tiles from AWS and Esri, and queries OpenStreetMap data for named summits. A separate library called soaring-core handles the flight math, atmospheric modeling, and lift prediction logic. The README notes important data limitations. OGN tracks depend on ground station reception, so gaps and truncations occur. Only aircraft registered in the OGN database appear, and positions are interpolated between received signals rather than showing exact paths. Attitude is estimated from track and speed since no real attitude data is transmitted. OGN also retains IGC tracks for roughly 24 hours, so older dates often have no replayable data. The full README is longer than what was shown.