顾及地形特征的等高线拓扑空间关系表达

在分析以往等高线树在表达地形图等高线拓扑空间关系时既没有考虑局部地形特征(鞍部、山头、洼地等)又不能很好表达等高线与所围区域之间的关系等缺陷的基础上,提出了增加地形特征等高线构建增量等高线树,以同时表达等高线之间、等高线与所围区域之间两种拓扑空间关系.通过建立等高线约束Delaunay三角网,给出了增量等高线树的动态提取算法.研究表明,增量等高线树在地形识别、基于等高线建立数字高程模型、等高线高程自动赋值、等值线充填等方面的表现都优于以往等高线树,具有较大的应用潜力.

Representation of topological spatial relations between contour lines based on terrain features

Former contour trees have two defects when describing the topological relations of contour lines on the map.One is that they did not consider local terrain features such as saddles,peak and pits;the other is that they can not express the adjacent relations of contour lines and their included region.An incremental contour tree which is built by adding the new contour lines describing terrain features is presented to represent the topological relations between contour lines as well as the topological relations between contour lines and their included region.The algorithm which is based on constrained Delaunay triangulation is put forward to build the incremental contour tree automatically and dynamically.Our researches demonstrate that the incremental contour tree has a great potency to make an improvement in many applications such as terrain identification,building digital elevation models based on contour lines,labeling contour lines automatically,color fill between contour lines and so on.