Had a quick search but couldn’t see anything on this. Is it possible, and if so how, to show all the locations for all events for that day in map view?
There is no public api for that, it possible to get all events for day in question, but after that you will need to use some kind of custom code to take location info from events and show it in some way.
Ah that’s a shame - it would be nice to be able to show all event locations grouped on one map. Oh well… 
Incidentally, is it possible to show a location on the map without knowing the longitude and latitude?
If the location of events have no latitude and longitude values in the database, you can activate the following option and the coordinates will be defined automatically during event loading
scheduler.config.map_resolve_event_location = true;It will try to get coordinates of event by location text