This paper introduces a displacement mapping algorithm that represents protruded shapes on the surface of an object. Two verticalsurfaces that are perpendicular to the underlying surface are added along the boundary of the polygon surface in order to represent pixels overflowing acrossthe boundary of the polygon surface. The proposed approach can accurately represent the silhouettes of protruded shapes. Using per-pixel instructions on graphics hardware, the approach is accelerated and executed in real-time. The proposed method provides an effective solution for the representation of protruding shapes such as high-rise buildings in an urban environment which can be used in location based applications of mobile electronic devices.