GPX Viewer & Editor (Elevation, Trim & Merge)

About the GPX Viewer & Editor (Elevation, Trim & Merge)

Open a GPS recording or a planned route — GPX, TCX, FIT (watches and bike computers), KML, KMZ or GeoJSON — and see it on a map coloured by speed, elevation, heart rate, cadence, power or grade, with linked charts of the elevation profile, speed or pace, heart rate, cadence and power. Point at the map or a chart and both show the same moment.

The stats are the ones runners, riders and hikers look for: distance measured on the Earth’s ellipsoid, moving time (moving faster than 0.5 m/s) and elapsed time, average and top speed and pace, elevation gain and loss without the GPS noise, highest and lowest points, heart rate, cadence and power, and splits per kilometre or mile. Then edit: trim, cut out a section, split, merge several files, reverse, remove GPS spikes, simplify for a device’s point limit, shift or rebuild times, add waypoints and hide the area around your start and finish — each step in an edit log you can undo. Your files are read on your device; nothing is uploaded.

Common uses

• Checking a run, ride or hike: distance, moving time, pace, climbing, heart rate and splits.
• Fixing a recording: trimming the drive home, removing a GPS spike, merging two halves of a ride.
• Preparing a route for a watch or bike computer with a point limit, as a FIT or TCX course.
• Sharing a track without showing where you live: the privacy zone hides the start and finish.

How the numbers are worked out

• Distance is measured between consecutive points on the WGS 84 ellipsoid with Vincenty’s formula (the shape GPS uses), not on a flat map; the gap between two parts of a recording is not counted.
• Moving time counts the time between two points while the speed is at least the moving threshold (0.5 m/s, a slow walk, by default); elapsed time runs from the first point to the last.
• Speed at a point is the distance over at least five seconds around it, so one jittery GPS fix does not make a top speed. Pace is time per kilometre or mile.
• Elevation gain and loss count each climb and drop of at least 3 m between turning points in full and ignore smaller wiggles, which on a GPS recording are mostly noise. Raise the threshold for a noisy GPS-only recording, lower it for a barometric altimeter.
• Grade is the height change over at least 40 m of distance.

The edits

• Trim keeps only the chosen section; Cut out removes it and leaves a gap; Split makes two tracks at a point, or several at every pause of a chosen length.
• Merge joins tracks in time order or in the order of the list, as one line or with gaps between them.
• Reverse turns a route around; its times still run forward from the same start.
• Remove spikes takes out points the track jumps to and back from faster than a speed you choose, and evens out height jumps.
• Simplify keeps the points that matter most to the shape (Ramer–Douglas–Peucker) until the track fits a point budget, such as a device’s course limit.
• Times: move every time by hours and minutes (a watch set to the wrong time zone), or give a planned route times at a steady pace, with an optional allowance for climbing (Naismith’s rule adds 10 minutes per 100 m).
• Waypoints: add one at any point of the track, rename or delete them.
• Privacy zone hides every point within a radius of the start and the finish, and the waypoints inside it.

The files you get

• GPX 1.1, as a track (with heart rate, cadence and temperature in Garmin’s TrackPointExtension and power as PowerInWatts) or as a route, checked against the GPX 1.1 schema.
• TCX: an activity with a time at every point, or a course for a device, with waypoints as course points (TCX keeps course names to 15 characters and course point names to 10), checked against the Training Center Database v2 schema.
• FIT course for watches and bike computers: the course, its points with heights and distances, and the waypoints near it as course points.
• KML for Google Earth (a timed track with its values, or a line), GeoJSON (RFC 7946) with times and values per point, and a CSV of every point with time, position, elevation, distance, speed, heart rate, cadence, power and temperature.

Reading FIT files

FIT is the binary format of most sports watches and bike computers. This page reads its activities and courses itself, from the file’s public structure: positions, heights, times, heart rate, cadence, power and temperature, the pauses of the timer (each pause starts a new part of the track) and the course points. Values a watch keeps in its own developer fields are skipped.

Limitations

• The map draws the tracks, waypoints and a grid, without a street or terrain background: nothing is fetched from a map server.
• Heights are the ones in the file; recorded GPS heights cannot be replaced with terrain heights here yet.
• A FIT course is made for one track; to send several, download them one at a time. Files up to 200 MB open.
• Heart rate, cadence and power can only be shown when the file carries them.

Privacy

On this device: nothing is sent

Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.