By using bipartite tree special property to depict the vertices and edges of linear hypertree,the authors obtain the counting formula and a series inferences of the linear hypertree isolated vertices,thus further the relation of degree sequence and linear hypertree are given.

Scan-line based contour tree generation method;

Former contour trees have two defects when describing the topological relations of contour lines on the map.

This paper builds the spatial relationship of contour using contour tree, forms the similar Douglas conversion model by means of convex-hull and Douglas arithmetic, and then puts forward a new method of automatically identifying the ridge line and the valley floor line.

Six popular height curve equations were adopted to fit with height curve and the results were assessed.

As we all know,height curve play an important role in the forest management and forest yield regulation.

A novel approach,curve tree,is proposed for curve representation and encoding.