one per line β Type 1/2/3/5/18/21 supported
Vessels (0)
Paste AIS data or load a sample to see vessel tracks.
Map
0 vessels Β· 0 positionsExport
GeoJSON output
0 features{
"type": "FeatureCollection",
"features": []
}Convert multiple AIS NMEA sentences into a GeoJSON vessel track and visualize it on an interactive map.
Paste AIS data or load a sample to see vessel tracks.
{
"type": "FeatureCollection",
"features": []
}Your vote is saved on this device only.
Paste raw AIS NMEA sentences and this tool reassembles them into vessel tracks you can see on an interactive map. It decodes position reports (types 1, 2, 3 and 18), AtoN reports (type 21) and static voyage data (type 5), groups positions by MMSI, handles multi-fragment messages and NMEA TAG-block timestamps, verifies each sentence checksum, and draws color-coded tracks with start and end markers.
It is built for marine engineers, AIS hobbyists, VTS and analytics teams who need to turn captured NMEA logs into mappable GeoJSON without command-line tools or paid services. It is free and runs entirely in your browser, so your AIS logs never leave your machine. Export the result as GeoJSON, KML or CSV, or filter down to a single vessel before downloading.
No. All parsing, track building and map rendering happen locally in your browser. The sentences you paste or upload never leave your machine, and nothing is sent to a server.
Position reports (types 1, 2, 3 and class B type 18) provide the track points, type 21 covers aids-to-navigation positions, and type 5 supplies the vessel name, callsign and destination. Other message types are counted but skipped because they carry no position.
Yes. Multi-part messages are buffered by their sequential ID and channel, then decoded once all fragments arrive. If sentences include a NMEA TAG block with a c: timestamp, those values are used to order the track chronologically.
Each sentence's checksum is verified, and any malformed line, failed checksum, incomplete fragment set or out-of-range coordinate is dropped and tallied under Skipped, with details listed in the skipped-sentences panel.
Each vessel becomes a LineString feature plus Point features for every report, tagged as start, end or position. Properties include MMSI, vessel name, point count, distance in nautical miles, SOG, COG, heading and navigation status.