High Altitude Balloon Path preview

Winds aloft → flight path → ATAK. Give it a launch point, a launch time and an ascent rate, and your browser asks SondeHub's public Tawhiri predictor where a high-altitude balloon will go. The waypoints, the altitude profile and the KML / KMZ / GPX / JSON exports are all built here, on your machine — nothing about your mission reaches my server.

Launch

Click the map to set the launch point, or type coordinates here.

Everything but letters, digits, - and _ is collapsed to a dash. The result prefixes every waypoint name and every export filename.
Read as UTC, not as your local clock. The desktop GUI labels this field UTC but parses it as local time; this page does what the label says.

Profile

Sea-level equivalent terminal rate.
A float flight that never descends gets a FLOAT-END waypoint and no LANDING waypoint. That is the desktop tool's behaviour, reproduced rather than papered over.

Waypoints

A sample interval of 0 means no time samples at all. Where the returned track is coarser than the interval, several sample times land on the same trajectory point and only the first is kept, so the T+NNNN numbering has gaps by design. Altitude bands capture the first crossing only — normally on the way up.
Altitudes shown as
Sets how altitudes read in the results panel and in exported waypoint descriptions. The desktop tool always writes both units; this toggle picks one.
Advanced
Must be a host that returns access-control-allow-origin. SondeHub's public Tawhiri does. A private or self-hosted instance without CORS headers is unreachable from a browser, whatever you type here.
Ready — click the map to place launch.

Map

  • track
  • launch
  • burst
  • float
  • landing
  • sample & band

Click to set the launch point; drag the launch marker to adjust. A flight that crosses the antimeridian draws as one straight line across the map — the exports split it correctly, the map does not.

Altitude vs time

Ascent, float and descent as returned by Tawhiri. Burst is the last ascent point; landing is the last descent point.

Results

Nothing predicted yet. Set a launch point and press Predict flight path.

    Export for ATAK

    Import KMZ in ATAK → Import Manager. UAS Tool: task recovery manually from landing point.

    These are ports of the desktop exporters — the same frozen KML style block, the same folder names, the same six-decimal coordinates — and are meant to be byte-identical to what the Python tool writes for the same prediction.