Extracting contour lines from scanned topographic maps

Contour lines are the main graphical element to characterize 3D terrain on 2D map sheets. The conversion of raster contour data to the corresponding vectors is still an interesting problem in the stage of research. In this paper, we suggest a contour extraction or simplification method, subsequently perform a fully automated, derivation of topographic map sheets containing simplified contour lines and inscriptions. The generated contour map is used to produce DEMs. The results concern the computation cost and the accuracy of the underlying contour lines information extracted.