计算LineString 长度百分数点坐标

1. 计算一条线上的指定分数的坐标，例如求两点之间的长度%1处的坐标，即可使用该方法获得。

lineSegment.pointAlong(): 计算该线段定义的直线长度的指定百分数的坐标。

percent=0.0: 返回段的起点；

percent = 1.0: 返回段的结束点。

0.0<percent<1.0: 返回点将位于段开始之前或结束之后

percent 为负数的时候，返回在延长线上的坐标

代码示例：

Coordinate end = new Coordinate(13504399.8685721, 3657960.0165479057, 0);

Coordinate start = new Coordinate(13504400.422609204, 3657953.2089571054, 1);

LineSegment lineSegment = new LineSegment(end, start);

Coordinate coordinate = lineSegment.pointAlong(-0.1);

System.out.println(coordinate.toString());

1. 坐标由new LineSegment(end, start) 参数1出发计算、lineSegment.pointAlong(-0.1), 长度-%1位置处的点坐标点

2. new LineSegment(start, end) 【调换参数位置】参数1出发计算、lineSegment.pointAlong(-0.1)，长度-%1位置处的点坐标

Coordinate end = new Coordinate(13504399.8685721, 3657960.0165479057, 0);

Coordinate start = new Coordinate(13504400.422609204, 3657953.2089571054, 1);

LineSegment lineSegment = new LineSegment(start, end);

Coordinate coordinate = lineSegment.pointAlong(-0.1);

System.out.println(coordinate.toString());

3. 坐标由new LineSegment(end, start) 参数1出发计算、lineSegment.pointAlong(0.1)

长度%1位置处的点坐标

Coordinate end = new Coordinate(13504399.8685721, 3657960.0165479057, 0);

Coordinate start = new Coordinate(13504400.422609204, 3657953.2089571054, 1);

LineSegment lineSegment = new LineSegment(start, end);

Coordinate coordinate = lineSegment.pointAlong(0.1);

System.out.println(coordinate.toString());

3.起点处坐标：lineSegment.pointAlong(0.0)

4.结束点坐标： lineSegment.pointAlong(1.0)