The map id is “mapp0” if there is one map on the page. Then second map is “mapp1” by default, and so on. The div containing the map also has the id “mapp0”, and the various layout parts are prefixed with that name, e.g. “mapp0_layout”, “mapp0_directions”, etc.
You can also specify a name in the shortcode using the name parameter, e.g. name=”mymap”.