GPX editor

How the editor works

Drop a GPX file at the top of the page. The file is parsed in JavaScript using a custom parser (no server round-trip) and the route appears on a map with an elevation profile and stats panel. From there, the six editing controls below the map each apply to the currently-loaded file.

Edits are sequential and stack: trim first, then smooth, then edit metadata. The map, elevation profile, and stats refresh after every operation so you can see the effect immediately. Reset edits reverts the working file to whatever you originally dropped, while Choose another file clears everything.

Download .gpx exports the current state as a standards-compliant GPX 1.1 file. If the input file contained Garmin TrackPointExtension fields for heart rate, cadence, or temperature, those are preserved in the export under the standard gpxtpx namespace.

Trim a recording

Trim removes points from the start, the end, or both. The most common use is cutting the warm-up rollout off a ride, the cool-down off a run, or the few minutes of car drive that leaked into the start of a hike recording.

The Trim control shows two range sliders — start and end. As you drag them, two dashed handles move on the elevation chart and the unselected portions dim, so you can line the cut up with a real feature like a saddle, a parking lot, or where pace changed. Apply trim drops every point outside the selected range, recomputes stats, and updates the elevation chart.

Trim is destructive within the working session — the original file is preserved and Reset edits restores it. For non-destructive workflows, download after each edit and keep the intermediate files. To compare the trimmed result against the original, drop both into the homepage viewer in separate browser tabs.

Reverse direction

Reverse flips every trackpoint so the route runs end-to-start. Hikers use this to do a thru-hike route southbound when the published GPX is northbound; cyclists use it to ride a loop the other way around.

The reverse operation strips timestamps. A reversed file with the original timestamps would have decreasing times, which some devices and apps reject as malformed. The result is a clean route file (no times, just an ordered list of points) ready to follow in the opposite direction. Elevation, heart rate, and other per-point data remain attached to their respective coordinates.

Reverse is a one-click operation in the editor — drop a .gpx, click Reverse direction, download the result. The output is a clean route file with no timestamps, ready to send to a head unit or platform that expects route-style data.

Merge two files

Merge takes a second .gpx file and appends its tracks to the current one. The output contains both as separate tracks inside a single GPX file. Bounds are unioned; total distance and elevation gain become the sum of the two inputs.

Common cases: stitching the morning and afternoon halves of a recording where the watch died at lunch, joining day-by-day recordings of a multi-day hike into one file, or combining a planned route with a recorded approach.

The merge does not concatenate the two tracks into a single track — keeping them separate preserves their individual names, types, and metadata. If a destination platform like Strava expects a single track, the safest path is to merge in viewmygpx and then trim if needed. The multi-day-hike sample file is a useful test case for the merge operation — four tracks in one file, ready to recombine in different shapes.

Split at a point

Split divides the route at any trackpoint and produces two .gpx files. The slider in the Split control picks the point; the preview shows how many points end up in each half. Generate split files runs the operation and exposes Download part 1 and Download part 2 buttons.

Unlike the other operations, split does not modify the working file. The output is two new GPX files; the editor stays on the original so you can split again at a different point if needed.

Common cases: separating a multi-day-hike file by overnight stop, cutting a long recording at the lunch break, or extracting just the climb portion of a ride for analysis. Splitting then re-merging in a different order is a workable way to swap halves.

Smooth elevation

Phone-recorded GPX files usually have noisy elevation. A bicycle climb that gains 800 m on paper might show 1,200 m on a phone because every wobble in the GPS altitude reading registers as a tiny climb-and-descent. Smoothing applies a rolling average to the elevation series, removing the noise without changing the coordinates.

The window size controls how aggressive the smoothing is. A window of 5 averages each point with the two before and the two after. Window 7 stretches that to three on each side. For typical phone noise, window 5–7 produces realistic gain numbers. Window 11 or higher starts removing real climbs and is rarely the right answer.

For desktop workflows, command-line tools like GPSBabel offer similar filters with extra knobs. The viewmygpx editor uses a centered rolling average — the simplest filter that handles typical noise without distorting the route shape.

Edit metadata

The metadata block of a GPX file holds the file's name and description. Many platforms (Strava, Komoot, AllTrails) display this name as the activity title when the file is uploaded. A file named "Track from device-EDGE-130" uploads as that exact string unless you rename it first.

The Edit metadata control updates both the file's metadata block and (when the file contains a single track) the track's own name and description. Setting both means the rename shows up no matter which field a downstream consumer reads.

For multi-track files (the output of a merge, for example), only the metadata block is updated; per-track names are preserved as they came in. To rename an individual track inside a multi-track file, split first, rename each part, then merge them back together.

Sources

• TopoGrafix — GPX: the GPS Exchange Format
• GPX 1.1 schema (XSD)
• GPSBabel — track simplification and smoothing filters
• Garmin — GPX TrackPointExtension namespace