A method for providing position information for controlling at least one function of an environment provided with an environment coordinate system comprises the steps of receiving image information associated with at least one image of at least one part of the environment captured by a camera of a mobile device, the mobile device being separate from the environment, determining a position associated with the mobile device in the environment coordinate system according to the image information associated with the at least one image, and providing position information indicative of the position associated with the mobile device in the environment coordinate system to control at least one function of the environment according to the position. There is also provided a method and system which provides movement information indicative of a movement associated with the mobile device relative to the environment coordinate system to control at least one function of the environment according to the movement.