| Filename extension | .gpx |
|---|---|
| Internet media type | application/gpx+xml |
| Initial release | 2002 |
| Latest release | 1.1 [1] / August 9, 2004 |
| Extended from | XML |
| Website | www.topografix.com/gpx.asp |
GPX, or GPS eXchange Format is an XML schema designed as a common GPS data format for software applications.
It can be used to describe waypoints, tracks, and routes. The format is open and can be used without the need to pay license fees. Its tags store location, elevation, and time and can in this way be used to interchange data between GPS devices and software packages. Such computer programs allow users, for example, to view their tracks, project their tracks on satellite images or other maps, annotate maps, and tag photographs with the geolocation in the Exif metadata.
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In GPX, a collection of points, with no sequential relationship (the county towns of England, say, or all Skyscrapers in New York), is deemed a collection of individual waypoints. An ordered collection of points may be expressed as a track or a route. Conceptually, tracks are a record of where a person has been, routes are suggestions about where they might go in the future. For example, each point in a track may have a timestamp (because someone is recording where and when they were there), but the points in a route are unlikely to have timestamps, because the author is suggesting a route which nobody might ever have traveled.
The minimum properties for a GPX file are latitude and longitude for a single waypoint. All other variables are optional.
Both Humminbird and Garmin use extensions to the GPX format for recording depth of water and other parameters.
Latitude and longitude are expressed in decimal degrees using the WGS 84 datum. Elevation is recorded in meters. Dates and times are not local time, but instead are Coordinated Universal Time (UTC) using ISO 8601 format.[1]
The following is a truncated (for brevity) GPX file produced by a Garmin Oregon 400t hand-held GPS unit. This document does not show all functionality which can be stored in the GPX format—for example, there are no waypoints or extensions, and this is part of a track, not a route—but the purpose is to serve as a brief illustration.