I have prepared a gpx file that shows the boundary of a new building. I have uploaded the file. Can I convert that trace into the outline of the building or does it have to be manually drawn again. Note this is a building rather than say a new path / road.
The help files all seem to discuss the upload, which I can do, not a conversion into a OSM feature.
JOSM can convert GPX-files into an OSM-datalayer.
Personally, I wouldn’t upload a GPX trace to OSM that was something other than an actual GPX trace. Among other things, it’ll appear in things like the public GPS layer. If you’ve got the outline of a building, I’d just use that as a guide in whatever editor you’re using (in the iD editor, you can just drag and drop GPX trace files onto it). You’ll likely also want to compare your “GPX building shape” with other data.