In time order
The order you add files in doesn't matter. Files and the points inside them are sorted by their timestamps, and repeated points are removed.
Merge IGC Files
Did your logger split one flight into two files? Join them into a single IGC file in time order, in your browser. Your files stay on your device.
Your files are read and merged in your browser. They are not uploaded to SkyViz.
How the files are merged
Overlaps stay clean
Where two files cover the same time, the file that started first is kept and the next one takes over after its last point. The track never jumps between two receivers.
One new file
You get one set of headers with the date of the first point, and the pilot, glider, and site from the first file that has them. Plain joined text would not be a valid IGC file.
The merged file keeps position, GPS and pressure altitude, and fix accuracy for every point. Other instrument data in the source files, such as tasks, events, and extra sensor columns, is not carried over.
To see a single file instead, use the IGC viewer. To turn the merged file into another format, use IGC to GPX or IGC to KML.
Frequently asked questions
How do I merge two IGC files?
Drop both .igc files on this page, in any order. Check the track and the notes that appear, then click Download merged IGC file. You can add more than two.
Will a merged IGC file pass signature validation?
No. A flight recorder signs a file with a G record, and that signature only matches the exact content it was made for. Merging changes the content, and only the recorder can sign, so the merged file has no G record and any validation check will fail it.
Can I submit a merged file to XContest or a competition?
Don't count on it. XContest's rules do not accept tracks compiled from more than one instrument, some of its national rules ask for a valid G record, and its rules tell pilots whose logger splits flights to contact the manufacturer. Competitions and record claims check the signature too. Use a merged file for your logbook, replay, and sharing, and keep the originals for anything official.
What happens if the files overlap?
The file that started first is kept, and the next file takes over after its last point. Points in the overlap are left out and counted above the download button. If a file adds nothing new, for example a copy of another file, you get a note saying so.
Can I merge files from different days?
Only if it is one flight that crosses midnight UTC, with a gap of up to six hours. An IGC file stores one date, and each point only has a time of day, so a file can roll over midnight once but can't describe separate days. Other combinations are refused rather than written with wrong times.
Can I merge two different flights from the same day?
Yes, but the result will read as one long flight, and its duration and distance will include the time between them. You get a note if there are more than 15 minutes between files, or if the position jumps further than a glider could fly in that time.
Are my files uploaded?
No. Your browser reads and merges the files on your device. A flight is only stored if you create an account and add it to your logbook.