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GPX fundamentals field answer 006

What is a GPX file, and what does it contain?

Reading time
6 minutes
Reviewed
Scope
File structure and route data

The short answer

A GPX file is a text-based XML file for exchanging GPS data. It can contain waypoints, routes and tracks, plus optional details such as names, elevations, timestamps and descriptions. It does not contain the map itself. The usable content depends on what the exporting service chose to include.

The format

GPX is a portable description of places and lines.

GPX stands for GPS Exchange Format. Topografix publishes the open GPX 1.1 specification, which defines a structured XML document for moving GPS information between devices and services. XML is plain text arranged in labelled elements, so software can identify coordinates and the information attached to them.

Every GPX document has a root element. Inside it, the file may include metadata, waypoints, routes, tracks and extension data. GPX 1.1 expresses coordinates using WGS 84 latitude and longitude. Measurements defined by the standard, including elevation, use metric units. The optional height field and its limits are covered in whether GPX includes elevation data.

The standard allows many fields to be omitted. Two valid GPX files can therefore carry very different amounts of information. One may contain only a simple line. Another may include a title, creator, timestamps, elevation values, descriptions and named points.

Inside the file

Three core data types do most of the work.

WaypointOne named position

A point can mark a summit, gate, water source or meeting place. Its name, description and elevation are optional.

RouteAn ordered plan

A route is a sequence of route points leading towards a destination. Software may use those points to describe an intended course.

TrackA recorded or detailed line

A track contains ordered track points, grouped into one or more segments. Each point may also carry time and elevation.

Metadata can describe the whole file, including its name, author, creation time or geographic bounds. Extensions allow a service or device maker to store additional information. Another app may ignore extension data it does not understand while still reading the standard GPX elements. GPX extensions explained separates those optional namespaces from the portable core.

The limits

The line is separate from the map and the ground.

  • No map tilesA GPX file supplies positions and lines. The receiving app provides its own map, which is why the same GPX can look different across apps.
  • No guarantee of turn instructionsSome exporters add names or proprietary guidance, but turn-by-turn instructions are not a required part of every GPX file.
  • No assurance of accessThe file cannot confirm that a path is open, lawful, safe or suitable today. Check current access and conditions separately.
  • No promise of completenessA .gpx filename does not prove that the document is valid or that it contains an ordered route or track.

A GPX file describes geographic data. It is not a live map, access notice or safety assessment.

Practical checks

Read the imported line before relying on it.

  1. Keep

    Retain the original download.

    It gives you a clean source if an import fails or a conversion changes the contents.

  2. Confirm

    Check that a route or track is present.

    A collection of waypoints alone does not provide the ordered line that beacen needs for route navigation.

  3. Review

    Inspect the start, finish and shape.

    Compare them with the route you intended to use. Check the reported distance and climbing as supporting clues.

  4. Protect

    Consider what the file reveals.

    Coordinates, timestamps and named points can disclose private locations or routines. Review the file before sharing it.

Sources & scope

What this answer is based on.

GPX permits optional fields and vendor extensions. The receiving app may not display every item written by the exporting service.

Continue with the format