GPX
Encyclopedia
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 waypoint
s, 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.
s. 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.
(UTC) using ISO 8601
format.
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.
Garmin International
Example GPX Document
4.46
4.94
6.87
XML schema
An XML schema is a description of a type of XML document, typically expressed in terms of constraints on the structure and content of documents of that type, above and beyond the basic syntactical constraints imposed by XML itself...
designed as a common GPS data format for software applications.
It can be used to describe waypoint
Waypoint
A waypoint is a reference point in physical space used for purposes of navigation.-Concept:Waypoints are sets of coordinates that identify a point in physical space. Coordinates used can vary depending on the application. For terrestrial navigation these coordinates can include longitude and...
s, tracks
GPS tracking
A GPS tracking unit is a device that uses the Global Positioning System to determine the precise location of a vehicle, person, or other asset to which it is attached and to record the position of the asset at regular intervals...
, 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
Geolocation
Geolocation is the identification of the real-world geographic location of an object, such as a radar, mobile phone or an Internet-connected computer terminal...
in the Exif metadata.
Data types
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 waypointWaypoint
A waypoint is a reference point in physical space used for purposes of navigation.-Concept:Waypoints are sets of coordinates that identify a point in physical space. Coordinates used can vary depending on the application. For terrestrial navigation these coordinates can include longitude and...
s. 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.
Units
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 TimeCoordinated Universal Time
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...
(UTC) using ISO 8601
ISO 8601
ISO 8601 Data elements and interchange formats – Information interchange – Representation of dates and times is an international standard covering the exchange of date and time-related data. It was issued by the International Organization for Standardization and was first published in 1988...
format.
Sample GPX Document
The following is a truncated (for brevity) GPX file produced by a GarminGarmin
Garmin Ltd. , incorporated in Schaffhausen, Switzerland, is the parent company of a group of companies founded in 1989 by Gary Burrell and Min Kao , that develops consumer, aviation, and marine technologies for the Global Positioning System...
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.
See also
- Concepts
- Point of InterestPoint of interestA point of interest, or POI, is a specific point location that someone may find useful or interesting. An example is a point on the Earth representing the location of the Space Needle, or a point on Mars representing the location of the mountain, Olympus Mons.The term is widely used in...
- OpenStreetMapOpenStreetMapOpenStreetMap is a collaborative project to create a free editable map of the world. Two major driving forces behind the establishment and growth of OSM have been restrictions on use or availability of map information across much of the world and the advent of inexpensive portable GPS devices.The...
, a collaborative project to create free editable maps using GPX traces.
- Point of Interest
- File Formats
- Exchangeable image file formatExchangeable image file formatExchangeable image file format is a standard that specifies the formats for images, sound, and ancillary tags used by digital cameras , scanners and other systems handling image and sound files recorded by digital cameras...
- Geography Markup LanguageGeography Markup LanguageThe Geography Markup Language is the XML grammar defined by the Open Geospatial Consortium to express geographical features. GML serves as a modeling language for geographic systems as well as an open interchange format for geographic transactions on the Internet...
- Keyhole Markup LanguageKeyhole Markup LanguageKeyhole Markup Language is an XML notation for expressing geographic annotation and visualization within Internet-based, two-dimensional maps and three-dimensional Earth browsers. KML was developed for use with Google Earth, which was originally named Keyhole Earth Viewer. It was created by...
, the equivalent format compatible with Google EarthGoogle EarthGoogle Earth is a virtual globe, map and geographical information program that was originally called EarthViewer 3D, and was created by Keyhole, Inc, a Central Intelligence Agency funded company acquired by Google in 2004 . It maps the Earth by the superimposition of images obtained from satellite...
.
- Exchangeable image file format
- Software
- GPSBabelGPSBabelGPSBabel is a cross-platform, free software to transfer routes, tracks, and waypoint data to and from consumer GPS units, and to convert between over a hundred types of GPS data formats...
, used to upload/download/convert GPX files - TCX, Garmin Training Center XML
- GPSBabel
External links
- GPX: the GPS Exchange Format
- Maplorer, Interactive online display of GPX tracks
- Garmin GPX extensions schema
- GPS mapping software, Conversion of GPX files into IMG file format