Replace noisy GPS or barometric altitude with accurate ground elevation, looked up by coordinate. Works on GPX, TCX and FIT files.
Drop your GPX, TCX or FIT file here
or click to browse
Looking up ground elevation for each point…
Good to know
Latitude and longitude come from satellite triangulation and are genuinely accurate to a few meters. Altitude from the same GPS signal is a different story, the geometry that makes horizontal position precise doesn't work nearly as well vertically, so raw GPS altitude can be off by tens of meters. Devices with a barometric altimeter usually do better day to day, but they drift with changing air pressure and can reset to the wrong reference point mid-activity, which is exactly what produces that one impossible spike or valley in an otherwise flat elevation profile.
This tool sidesteps the sensor entirely: for every point in the file, it looks up the actual ground elevation at that exact latitude and longitude from a global elevation dataset, and replaces the recorded altitude with it. The route itself, its coordinates and timestamps, never changes, only the height values do. That's also the only thing that leaves your device to make this work: the coordinates, sent to a free elevation lookup service, nothing else. The file stays local, nothing is stored on the other end, and the result downloads straight back to your browser in whichever format you need.
FAQ
GPS altitude is the least accurate part of a GPS signal, often off by tens of meters. Devices with a barometric altimeter do better but drift with weather changes, or reset to a wrong reference point mid-activity, which is what usually causes a sudden fake climb or drop in the middle of an otherwise flat route.
It replaces every point's altitude with ground elevation looked up from its exact latitude and longitude, using a global elevation dataset instead of your device's sensor reading. The route itself, its coordinates and timestamps, is untouched.
No, the file never leaves your device. Only the coordinates (latitude and longitude, nothing else) are sent to Open-Meteo's free elevation API to look up ground height. No file, no name, no account, nothing is stored on their end.
It uses a global dataset at roughly 90-meter resolution, accurate enough to fix GPS spikes and barometric drift, but it won't capture every small dip or rise a precise local survey would. For everyday elevation gain and route profiles, it's a solid improvement over raw consumer GPS altitude.
Yes, upload any of the three and download the elevation-corrected result in whichever of the three you need.
Once the elevation is right, the same file works directly in the map poster editor.
Open the editor →