What is the TRK file format?
The .trk file format was developed by CompeGPS Team and falls under the category of a data file stored in text formatting. It is used by the CompeGPS Land program (now TwoNav Land) that interfaces with GPS devices. The file contains a series of track points - each recording longitude, latitude, altitude, date/time, and speed - laid onto a map to help with the planning of routes and navigation on GPS devices.
A second, older dialect of .trk originates from Garmin's PCX5 software; the two formats use different field layouts and headers and are not interchangeable without conversion. The open-standard .gpx (GPS Exchange Format, XML-based) has largely replaced .trk for sharing GPS tracks between applications. GPSBabel supports both .trk dialects and can convert them to GPX, .kml, and many other formats.
Various programs on Linux, Windows, and Mac can be used to open and read .trk files.
Security & safety
RISK: LOWPlain text GPS data files pose no security risk. Privacy concern: a track file reveals precise location history including timestamps. Do not share .trk files from personal routes without trimming location data near home or sensitive areas.
Format details
in a nutshell- Garmin IMG map TRK subfile - A binary subfile within Garmin .img map files storing road/trail geometry; unrelated to the text GPS track log format.
- Various game/3D engine track formats - Several games and 3D applications use .trk for racing tracks or animation tracks; context-dependent and not related to GPS.
Programs that open TRK files
Windows3 apps
GPSBabel
Open-source Use GPSBabel GUI or CLI to open, view, and convert .trk files. Select 'compegps' or 'garmin_pcx5' as input format. 
TwoNav Land (formerly CompeGPS Land)
Freemium Open the .trk file natively; view on map, edit, and export to other formats.
Google Earth Pro
Free Google Earth cannot open .trk directly - convert to KML/GPX first using GPSBabel, then import. 
macOS1 app
Linux1 app
Technical details
deep spec| Format type | Plain text, comma-separated values (CompeGPS/TwoNav dialect) or space-delimited (Garmin PCX5 dialect) |
| Coordinate system | WGS84 geographic coordinates (longitude/latitude); projection configurable in CompeGPS header block |
| Track point fields | Longitude, latitude, altitude, date/time stamp, and speed recorded per track point |
| Header metadata | Track name, display color, coordinate system, projection, and datum (CompeGPS variant) |
| Dialects | CompeGPS/TwoNav and Garmin PCX5 - incompatible field orders and headers; conversion required between them |
| Modern replacement | GPX (GPS Exchange Format) XML standard is the current interoperable open format for GPS tracks |
| Conversion tool | GPSBabel converts both `.trk` dialects to GPX, KML, and dozens of other GPS formats |
| Encoding | ASCII / Latin-1 plain text |
| Typical file size | 1 KB - 2 MB depending on the number of recorded track points |
| Native software | TwoNav Land (formerly CompeGPS Land) is the primary editor; Google Earth Pro can display converted files |
| Unrelated binary variant | The Garmin IMG map subfile format also uses the `.trk` extension but is entirely binary and unrelated |
| Compression | None - track points stored as uncompressed delimited text |
| Released | mid-1990s (Garmin PCX5 era); CompeGPS variant circa early 2000s |
TRK conversions
Community Q&A
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