我有两个GPS坐标连接在一起形成一条线。我还有一个GPS点,它靠近,但从未完全在线上。我的问题是,如何找到沿给定点的最近点?
答案 0 :(得分:11)
Game Dev has an answer to this,它在C ++中,但它应该很容易移植。哪个CarlG有kindly done(希望他不介意我重新发布):
public static Point2D nearestPointOnLine(double ax, double ay, double bx, double by, double px, double py,
boolean clampToSegment, Point2D dest) {
// Thanks StackOverflow!
// https://stackoverflow.com/questions/1459368/snap-point-to-a-line-java
if (dest == null) {
dest = new Point2D.Double();
}
double apx = px - ax;
double apy = py - ay;
double abx = bx - ax;
double aby = by - ay;
double ab2 = abx * abx + aby * aby;
double ap_ab = apx * abx + apy * aby;
double t = ap_ab / ab2;
if (clampToSegment) {
if (t < 0) {
t = 0;
} else if (t > 1) {
t = 1;
}
}
dest.setLocation(ax + abx * t, ay + aby * t);
return dest;
}
答案 1 :(得分:2)
试试这个:
ratio = (((x1-x0)^2+(y1-y0)^2)*((x2-x1)^2 + (y2-y1)^2) - ((x2-x1)(y1-y0) - (x1-x0)(y2-y1))^2)^0.5
-----------------------------------------------------------------------------------------
((x2-x1)^2 + (y2-y1)^2)
xc = x1 + (x2-x1)*ratio;
yc = y1 + (y2-y1)*ratio;
Where:
x1,y1 = point#1 on the line
x2,y2 = point#2 on the line
x0,y0 = Another point near the line
xc,yx = The nearest point of x0,y0 on the line
ratio = is the ratio of distance of x1,y1 to xc,yc and distance of x1,y1 to x2,y2
^2 = square
^0.5 = square root
在我们发现从点x0,y0到线(x1,y1 - > x2,y3)的距离之后导出公式。 见here
我在这里测试了这段代码(我上面给你的这个特别的代码),但几年前我用过类似的方法,它可以用来试试。
答案 2 :(得分:0)
您可以使用JTS。
非常简单的代码示例:
// create Line: P1(0,0) - P2(0,10)
LineSegment ls = new LineSegment(0, 0, 0, 10);
// create Point: P3(5,5)
Coordinate c = new Coordinate(5, 5);
// create snapped Point: P4(0,5)
Coordinate snappedPoint = ls.closestPoint(c);