Tracking back on a referral to this site from a Dutch site I found that this tool RTWtool was available for download for navigation file modifications. The Manual/help file will give you an idea of its capability.
I have a small test GPX file with waypoints added, the waypoints have an extra description field. Let’s see if this will convert to a TCX file for use on the Wahoo with course points.
To start use [Open File] and find the file to process, its location address is then shown. Then select Course file(.tcx/.fit) as the Export to format. The number of tracks and waypoints found will be shown: here’s mine.
In the import Tab you can highlight and double click on either the track or the Waypoints to open them in a map view, or use the SHOW ON MAP button. Clicking on the Waypoint in the map view will show you all the data available for the waypoint.
To convert the GPX first select export as COURSES in the drop-down menu and my preference is to un-tick the add course points as I don’t require turn instructions. For the waypoints select export as COURSE POINTS
Then the [CONVERT] button will save the converted file in your chosen location and populate the Export tab which can then be viewed. Note the Exported TCX file is shown without any course point info. Double click the course and it will be shown with Course point markers.
If you change your mind and want to add turn instructions then TICK the “Add Course Points” Modification Box and use the CONVERT button again. you can re-save with a different name, or over-write your original file. At the bottom of the export window there is a summary of the course file – mine stated: CourseLength 26.6Km, 169 track points, 41 Course points.
On loading the file to the Wahoo it produces the following.
Settings to modify
Check the manual, you can change the individual Waypoint symbols, or add waypoint warnings, unfortunately the Wahoo will not identify with a waypoint in a TCX file yet.
We all have some favourite tool to create our route GPX with added Waypoints but you might not have the capability for all the waypoint info as shown in my preview map above. You can open any GPX file with a text editor such as notepad and the waypoint is setup as follows:
<wpt lat="52.4074289931319" lon="-0.647031016469841"><ele>135.489687778987</ele><time>2019-07-21T09:17:54Z</time><name>X-roads</name><desc>long way for fun</desc></wpt>
Once converted to a TCX file the Wahoo uses the secondary DESC field not the primary NAME field which is the reverse you would expect to happen.