In order to build a good TIN(Triangulation Irregular Network), this paper advances a DTM method of incremental insertion modified by W=dx 1×dy 2-dx 2×dy 1.

After reviewing simply prevalent generation algorithms of Delaunay triangulation, divideconquer, incremental insertion and triangulation growth,presents a fast and efficient triangulation algorithm on the base of incremental insertion,the scattered data on 2D shape are triangulated by this algorithm.

They fall into three broad categories: divide\|and\|conquer, incremental insertion and triangulation growth.

It presents the status of Delaunay triangulation methods,which consists of two steps,firstly,constructing Delaunay triangulation by incremental insertion algorithm,and them inserting constrained boundary by multiple diagonal exchanging algorithm to form constraint Delaunay Triangulation.

This paper studied incremental insertion algorithm,which is one of the methods of Delaunay triangulation,analyzed the key steps which affect the efficiency of algorithm mostly of all the steps of the algorithm.

This paper describes the basic theory of Delaunay triangulation grid generation method that are widely applied at present,analyzes the principle of several popular DT(Delaunay Triangulation) algorithms,such as incremental inserting algorithm,partition algorithm,triangulation network growth algorithm,etc.

That actualizes the large amount of scattering data into three-dimensional modeling by incremental insertion method,for that to realize the showing of the 3D image,and designs the arithmetic to show the cross sectio.