I like the way that OSM presents relation/way/area; for example:
I would like to generate a map (likely using gpsvisualizer) that combines these two relations with other way/area/node and also some of my own data (GPX format).
When I download XML from OSM using link in above relation page; it only contains a list of ways. How can I obtain a file for the above relations that contains coordinates?
If you potentially want to do this for any relation (or way, or whatever) then you could try throwing your OSM data into a database with e.g. osm2pgsql, and fetching data from that follow the switch2osm guide and use a very limited stylesheet).
This is probably some way from what you are trying to do, but I thought I’d mention it just in case.