Study on Automated Aggregation of Depth Contour on Nautical Charts

An automated method for aggregating depth contour based on triangulation is proposed. Firstly, an automatic method to detect aggregating contours is proposed, which doesn't need to reco-gnize the submarine topography features. Secondly, triangles to construct the bridge areas are filtered, and the bridge areas are expanded and related "holes" are filled. Next, the bend areas to generalize are detected. Then generalized areas are derived by merging the bride areas and generalizing bend areas, and then the aggregated result contours are achieved by conducting symmetric difference calculation on the boundary of generalized areas and the aggregating contours. Test results show that the method proposed in this paper can detect the aggregating contours correctly, and the aggregated results not only can guarantee navigation safety but also can achieve a legible and smooth depth contour.