iD/data/doc/04-gps.md

GPS

GPS data is the most trusted source of data for OpenStreetMap. This editor supports local traces - .gpx files on your local computer. You can collect this kind of GPS trace with a number of smartphone applications as well as personal GPS hardware.

For information on how to perform a GPS survey, read Surveying with a GPS.

To use a GPX track for mapping, drag and drop the GPX file onto the map map editor. If it's recognized, it will be added to the map as a bright green line. Click on the 'Background Settings' menu on the left side to enable, disable, or zoom to this new GPX-powered layer.

The GPX track isn't directly uploaded to OpenStreetMap - the best way to use it is to draw on the map, using it as a guide for the new features that you add.