A Fast Algorithm of Color Fill between Contours Based on Grid Data

Based on contour tracing for grid data,a fast algorithm of color fill is proposed to cope with random boundaries surrounding data gaps and to realize the vector effect of color fill graph. From the relationship between boundary lines and unclosed contours,the topologic structure among contours can be built and stored in a tree structure.Such a topologic structure displays the linking and closing between boundary lines and unclosed contours,the nesting among closed polygon in the order of tree rings.It is successfully applied in mapping of huge volume of submarine topographic data observed by multibeam,and it overcomes the inconsistency between color blocks and contours produced by mapping software for multibeam postprocessing.