Simplifying line with oblique dividing curve method

It has been found that line simplification is one of the most important aspects in automated cartographic generalization. Most of current line simplification algorithms only consider one curved section of line the shape of which during curve dividing and generalization, is not enough to preserve the whole shape of line. This paper puts forward a new approach of line simplifying termed as "oblique dividing curve" method. The approach divides curves into monotone arcs with oblique section and pays attention to curve shapes on both sides of line; At first, it identifies whether each monotone are is U-type or V-type arc, big or small arc, and then generalize different type of arcs with different details; during the course of generalization, if one arc is simplified, the approach will re-divide the whole line into new arcs, and simplify them one by one again, or the next arc will be simplified. The rest may be deduced by analogy. Thus the algorithm is a dynamic simplifying process. Example shows that the algorithm is more excellent in the aspects of holding line feature, U-type and V-type arcs, big curvature, whole shape and so on, and undergoes a high simplifying rate, which fully proves its scientificalness and advantage.