Conflating two polygonal lines

A basic technique in comparing and detecting changes in geographical spatial data from satellite images consists of identifying linear features or edges in the image and then matching those features. A chain of connected linear features which form a polygonal line is used as the basic unit for matching two images. We develop a distance measure between two polygonal lines and an efficient algorithm for conflating or optimally matching two polygonal lines based on this distance measure. We show that some of the alternative approaches used in the literature, including Hausdorff's distance, fail to satisfy the basic requirements of a distance measure for image conflation.