Self-propelled device and method for orienting such a device

The method involves performing an automatic division of a total area (BG) of a floor into subsections (T1-T8) according to a predetermined area size of geometric primitives, and different floor coverings, where the geometric primitives are in square, circle, rectangle and/or triangle shape. The subsections having same size are detected. Distance between two opposite walls is compared with predetermined values that correspond to a door width for determining a surface area as a door area. An independent claim is also included for an automatic movable apparatus comprising a sensor.