A novel approach, Included Angle Chain, is presented for curve representation and encoding. In this framework, a curve is modeled by a number of linked equi-length line segments and a sequence of codes using the included angles between a pair of neighboring line segments is used for representing the curve. The number of the segments is determined by an area criterion, and the curves to be matched are represented by an included angle chain of the same length. The representation is invariant to rotation, scaling, and translation. A practical use of the proposed approach is to register a SAR (synthetic aperture Radar) image of certain region with maps.