digitransit-ui/docs/Location.md

Location has two functions. Firstly, it marks routing start and stop location and possibly a routing via point. Secondly, from location can be used for nearby stop search.

State	Description
No location	We have no location information set
From Location set	User's from location is set
To Location set	User's to location is set
Route set	Both from and to locations are set
Route via point set	Both from and to locations are set and also a route via point