两个点的线性插值定点数算法

说明：1、基本公式 y=( y2-y1 ) ( x-x1 ) / ( x2-x1 ) + y1

2、根据直线斜率的正负、内插外插的不同，分为6种情况。

3.参见文件夹中的“插值算法的6种情况”一图。-two points of linear interpolation algorithm for determining points : one, the basic formula y = (y2 - y1) (x-x) / (x2 - x1) y1 2, according to the slope of the linear positive and negative, interpolation, extrapolation of different, divided into six kinds of situations. 3. See folder "interpolation algorithm for the six species of" a map.