1. A device for surveying a surface in a real world coordinate system, the device comprising a pattern projecting unit adapted for projecting a predefined pattern onto the surface; an optical measurement system adapted for determining positional and image data of a projected pattern on the surface, wherein the positional and image data are indicative of the predefined pattern in a measuring coordinate system; a processing unit adapted for determining transformation data based on the predefined pattern and the determined positional and image data of the projected pattern, the transformation data allowing a transformation between the real world coordinate system and the measuring coordinate system to thereby survey the surface.