用三角网法绘制等值线，是在三角形的三条边上用线性内插方法寻找等值点，这种方法的机理是将每个三角形看作是空间的一个平面，这就要求在每个三角形的三个顶点内的地貌形态无明显的变化，故此希望将其中最靠近的三个点构成三角形，以符合上述机理，使插补的等值点精度较高，更好的反映地貌的实际形态。符合这些条件的三角形称之为“最佳三角形”-With a triangular mesh contour map is the edge of the triangle with the three methods of linear interpolation to find the equivalent point, the mechanism of this method is to each triangle as a space plane, which requires each triangles three vertices with no obvious patterns of geomorphic change, it wished to put the three points closest to constitute a triangle in order to comply with the above mechanism, so that the equivalent interpolation points higher accuracy, better reflects the landscape the actual shape. Applying these criteria to the triangle known as the