The rotation angle

When the viewpoint of the ground matches the viewpoint of the world, the blue axis belonging to the ground runs from the center point toward the south.

When the camera has the same viewpoint as the ground the camera is located at the center point of the ground and is oriented towards the south.

If we rotate the camera by 135 degrees to the RIGHT, (or rotate it by 225 degrees to the LEFT), the camera will be oriented toward the northwest.

Rotation by 180 degrees in either direction causes the camera to be oriented to the north. 

Other rotation angles cause the camera to be oriented in other directions.