Convert GPS tracks
Converting GPS tracks is a simple process that may be required before you can upload your recorded tracks. OpenStreetMap requires that GPS tracks are saved using the XML-based GPS Exchange Format (.gpx file type). Although some GPS receivers allow you to save the data as GPX, many have their own data format. If your GPS device uses its own format you will need to convert the track log file. This can be as simple as using an online conversion tool.
Converting between formats
Online conversion tools
GPSVisualizer.com provides a free online conversion tool. Simply upload your GPS track file, select GPX as the output format and click "Convert". The resulting file can then be saved to your computer before uploading to OpenStreetMap. (If your original track file does not contain time data, you can have GPS Visualizer add simulated timestamps by selecting "Add artificial timestamps" in the Advanced Options section of the conversion form.)
Offline conversion tools
GPSBabel is a free download available for Windows, Mac and Linux. It is a versatile tool that can convert between many of the popular GPS track file formats, see also guide how to GPSBabel/Convert tracelogs to GPX. For a list of supported GPS data formats and other conversion tools, see List of GPS trace file formats. Other software that is relevant to OpenStreetMap and is available for a variety of platforms, including mobile devices, is listed under Software.
What formats are supported?
The server understands standard GPX Version 1.0 and 1.1, except that the tag
<time> must be present on every track or way point. For uploading trackpoints lacking proper timestamps see Farzaneh's user page.
The geographic datum of OpenStreetMap worldwide is WGS-84, so please make sure your uploaded tracks are in WGS-84 lat/lon. GPX files should always be in WGS-84, but you have to be careful if you convert your tracks from other formats (and possibly other datums) to GPX.
Multiple tracks in one GPX file
You can upload multiple disjunct tracks inside one GPX file if they are in separate segments, i.e. each is enclosed with "<trkseg> ... </trkseg>". Otherwise the file is regarded as one continuous track and lines will be drawn between all points. For instance, if you have a track segment from New York and a track segment from London in the same GPX file without marking them as separate segments, they would be linked together with a huge line across the Atlantic.
If you want to split files with multiple tracks (i.e. <trkseg> stanzas), you can use gpxsplitter, which splits multi-track GPX files, containing waypoints, into individual one-track GPX files with their respective waypoints.