The method I use (probably not the best, but one which works) is to have a battle field beneath the main map. When battle ensues:
1) The characters stay exactly where they are but are frozen.
2) Their 'combat' counterparts are unfrozen.
3) The opponents are added.
4) The world camera is hidden.
5) The main combat camera is unhidden (I have four cameras for combat).
6) Combat begins
When over:
1) View switches back to world map.
2) Character positions reset
3) Monsters removed.
Like I said, im sure there are better methods, but this one works well for me.
1) The characters stay exactly where they are but are frozen.
2) Their 'combat' counterparts are unfrozen.
3) The opponents are added.
4) The world camera is hidden.
5) The main combat camera is unhidden (I have four cameras for combat).
6) Combat begins
When over:
1) View switches back to world map.
2) Character positions reset
3) Monsters removed.
Like I said, im sure there are better methods, but this one works well for me.