When getting input from either the horizontal or vertical axis of the joystick (I’m using an Xbox 360 controller), I get a lower value when the stick is completely tilted towards the corners compared to the sides (about 0.7 and 1.0 respectively). This shows that the boundary for the axis is a circle.
However, this means that my character controller will move slower when moving diagonally compared to the sides. This issue would be resolved if I could change the boundary to a square so the corners would return 1.0.