there are only few starting position for each map, if the map is 2v2, then there are 4 starting position, its fixed, but if only 2 players using a 2v2 map, then 2 of them will be nothing, and where they are ? its perfectly random. if its a 1v1 map, and the other starting location is exactly opposite of you, the map should looks like a mirror. and you should not use scanner to look for the player, should spend a scv or a marine walking around of all the possible starting location, if you scout early on, your scv will be able to survive most likely, if a marine, since u got 1, that mean your opponent also got 1 or more when u arrived, so higher chance it cant see the next sun rise.