GPX Smoother

This very useful GPS Smoother was created by Brenda Zysman - and allows you load a gpx file and apply a few different "smoothing" algorithms to the elevation. The resulting gpx file can be copied and saved to a file and then imported into your Tacx trainer.

Smooth - uses simple box-score smoothing to smooth the elevation over 5 points.

Set Range - lets you set the maximum and minimum slope.

Flatten - lets you set the maximum change in slope between any two points.

Slide the triangular handles on the smaller graph to select only a portion of the ride to smooth. This allows you create a ride similar to a Slope-Distance Catalyst ride.


1. Select a gpx file:
Missing elevation tags have been added and set to a value of 100 meters.
2. If your gpx file does not contain elevation data, you can add elevation values. This could be a slow process, depending on the number of points in your gpx file. The elevation service is subject to usage limits of 25,000 total locations per 24 hour period, so this functionality may be temporarily unavailable.
3. Smooth the data:
4. Check out the resulting slope. Hover over a point to see details:
Original New Slope
Average Slope:
5. Slide the triangles in the graph below to zoom in on a portion of the ride and to select that portion of the ride to be smoothed.
8. Try different smoothing:
This file is too large to download, please copy and paste the result in step 6 instead.
8. If the download button does not work, copy (right click, Select all, Copy) the contents of the box below (which contains the resulting gpx) and save to a gpx file.

The GPS Smoother is provided free of charge with the permission of the author and hosted by Lunicus. Any issues arising from use are not the responsibility of the owner or Lunicus.