Preserve extra information from TCX / support saving

[richlv]

I sometimes recommend JOSM for things that are not directly OSM-related, like GPX editing.
This makes JOSM an outreach tool - once people already have it, they can easily try some OSM stuff, too :)

There's one area I haven't been able to suggest JOSM - editing TCX files (trimming or merging them, aligning extremely bad GPS points etc).
The convert_to_data-edit-convert_back cycle only allows saving to GPX, losing all the extra info.

If it's reasonably easily to do, it would be great to preserve all this info. If I recall correctly, something similar happens for some data in GPX.
This might need extra support for exporting, not sure how feasible that is.

TCX opening is supported by ​https://wiki.openstreetmap.org/wiki/JOSM/Plugins/dataimport .

[taylor.smock]

The dataimport plugin would have to add a menu entry -- it would not be possible for it to add a menu item to the right-click menu of an OSM Data Layer (at this time; we could technically add a method for plugins to add arbitrary actions, but I don't think we'll do that right now).

So the dataimport plugin would probably want to add some kind of export menu.

[richlv]

For GPX, converting data back to GPX and then saving also works - but not sure whether "convert to GPX" wouldn't drop the extra data already.