Java：计算两点之间的角度（以度为单位）

Question

我需要计算我自己的 Point 类的两点之间的角度（以度为单位），点 a 应为中心点。

方法：

public float getAngle(Point target) {
    return (float) Math.toDegrees(Math.atan2(target.x - x, target.y - y));
}

测试 1： // 返回 45

Point a = new Point(0, 0);
    System.out.println(a.getAngle(new Point(1, 1)));

测试 2： // 返回 -90，预期：270

Point a = new Point(0, 0);
    System.out.println(a.getAngle(new Point(-1, 0)));

如何将返回结果转换为 0 到 359 之间的数字？

Answer 1

您可以添加以下内容：

public float getAngle(Point target) {
    float angle = (float) Math.toDegrees(Math.atan2(target.y - y, target.x - x));

    if(angle < 0){
        angle += 360;
    }

    return angle;
}

顺便说一下，为什么您不想在这里使用双精度？

Answer 2

我从 johncarls 解决方案开始，但需要调整它以获得我所需要的。
主要是，当角度增加时，我需要它顺时针旋转。我还需要 0 度来指向北。他的解决方案让我很接近，但我决定也发布我的解决方案，以防它对其他人有帮助。

我添加了一些附加注释，以帮助解释我对该函数的理解，以防您需要进行简单的修改。

/**
 * Calculates the angle from centerPt to targetPt in degrees.
 * The return should range from [0,360), rotating CLOCKWISE, 
 * 0 and 360 degrees represents NORTH,
 * 90 degrees represents EAST, etc...
 *
 * Assumes all points are in the same coordinate space.  If they are not, 
 * you will need to call SwingUtilities.convertPointToScreen or equivalent 
 * on all arguments before passing them  to this function.
 *
 * @param centerPt   Point we are rotating around.
 * @param targetPt   Point we want to calcuate the angle to.  
 * @return angle in degrees.  This is the angle from centerPt to targetPt.
 */
public static double calcRotationAngleInDegrees(Point centerPt, Point targetPt)
{
    // calculate the angle theta from the deltaY and deltaX values
    // (atan2 returns radians values from [-PI,PI])
    // 0 currently points EAST.  
    // NOTE: By preserving Y and X param order to atan2,  we are expecting 
    // a CLOCKWISE angle direction.  
    double theta = Math.atan2(targetPt.y - centerPt.y, targetPt.x - centerPt.x);

    // rotate the theta angle clockwise by 90 degrees 
    // (this makes 0 point NORTH)
    // NOTE: adding to an angle rotates it clockwise.  
    // subtracting would rotate it counter-clockwise
    theta += Math.PI/2.0;

    // convert from radians to degrees
    // this will give you an angle from [0->270],[-180,0]
    double angle = Math.toDegrees(theta);

    // convert to positive range [0-360)
    // since we want to prevent negative angles, adjust them now.
    // we can assume that atan2 will not return a negative value
    // greater than one partial rotation
    if (angle < 0) {
        angle += 360;
    }

    return angle;
}

Answer 3

基于萨阿德·艾哈迈德的回答，这是一种可用于任意两点的方法。

public static double calculateAngle(double x1, double y1, double x2, double y2)
{
    double angle = Math.toDegrees(Math.atan2(x2 - x1, y2 - y1));
    // Keep angle between 0 and 360
    angle = angle + Math.ceil( -angle / 360 ) * 360;

    return angle;
}

Answer 4

为什么每个人都把事情复杂化？

唯一的问题是 Math.atan2( x , y)

正确的答案是 Math.atan2( y, x)

他们所做的只是混合 Atan2 的变量顺序，导致它反转旋转程度。

你所要做的就是查找语法
https://www .google.com/amp/s/www.geeksforgeeks.org/java-lang-math-atan2-java/amp/

Answer 5

Math.atan( double) 非常清楚，返回值的范围可以是 -pi/2 到 pi/2。所以你需要补偿该返回值。

Answer 6

如果您想要从北开始的“方位”度数，那么：

Direction	Degees
North	0
North East	45
East	90
South East	135
South	180
South West	-135
West	-95
North West	-45

您可以这样做：

public static final double RAD_360_DEG = Math.PI * 360d / 180d;
public static final double RAD_180_DEG = Math.PI * 180d / 180d;
public static final double RAD_90_DEG = Math.PI * 90d / 180d;

/**
 * @return The angle from north from p1 to p2.  Returns (in radians) -180 to 180, with 0 as north.
 */
public static double getAngleBearing(double p1x, double p1y, double p2x, double p2y) {
    double result = Math.atan2(p2y - p1y, p2x - p1x) + RAD_90_DEG;
    
    if (result > RAD_180_DEG) {
        result = result - RAD_360_DEG;
    }
    
    return result;
}

double bearingAngle = Math.toDegrees(getAngleBearing(...));

Answer 7

angle = Math.toDegrees(Math.atan2(target.x - x, target.y - y));

现在，将圆形值的方向保持在 0 到 359 之间的角度可以是：

angle = angle + Math.ceil( -angle / 360 ) * 360

Answer 8

我的实现：

private double searchAngle(Point posOne, Point posTwo) {
  int sumPos = (posOne.x * posTwo.x) + (posOne.y * posTwo.y);
  double moduleOne = Math.sqrt( (posOne.x * posOne.x) + (posOne.y * posOne.y) );
  double moduleTwo = Math.sqrt( (posTwo.x * posTwo.x) + (posTwo.y * posTwo.y) );

  return Math.toDegrees( Math.acos( sumPos / (Math.abs( moduleOne ) * Math.abs( moduleTwo )) ) );
}

输入：

• posOne：（x = 50，y = 43）
• posTwo：（x = 12，y = 42）

输出为

• 33.35907305958513

（以度为单位）。

Answer 9

怎么样：

angle = angle % 360;