In my opinion it would be nice if the query was included as a url param so that reload preserves results. For example:
/maps#13.73/-37.799/144.8809?q=chemist
Additional params or child route on pin click could allow browser back button (not UI < back
button) to work as expected too. Maybe:
/maps#13.73/-37.799/144.8809?q=chemist&pin=1
Obviously I have no idea about the actual information architecture and routing logic but I hope the general idea makes sense.