In reply to rodw:
The red arrow points in the direction of phone orientation. But that could either be the top (the camera end) of the phone for portrait view of the map, or the side of the phone for landscape view. That's a difference of 90 degrees which can cause directional confusion momentarily, if the phone has switched orientation after being in your pocket.
When I take my phone out, I make sure to hold it upright for a few seconds to get it back into portrait view, then press the crosshairs button (bottom left) to get my location into the centre of the screen.