如何计算斜边和方位

Question

我从@DanS 在此链接how-to-display-a-map-still-image-file-with-a-moving-current-location 获得了以下代码

onCurrentPosition(Location current){
    double hypotenuse = upperLeft.distanceTo(current);
    double bearing = upperLeft.bearingTo(current);
    double currentDistanceX = Math.cos(bearing) * hypotenuse;
    //                     "percentage to mark the position"
    double currentPixelX = (currentDistanceX / upperLeft.distanceTo(lowerRight) * Math.cos(upperLeft.bearingTo(lowerRight))) * mapWidth;

    moveIndicatorX(currentPixelX);
}

以下是值：

• 当前：41.850033,-87.65005229999997
• 左上：41.866514127810355,-87.6720142364502
• 右下：41.83397145565242,-87.62824058532715
• 地图宽度：512 x 512 像素

这是位置、斜边（距离）、方位角（方位角）的在线计算器

• convert LatLng to Location format(e.g. 41° 51′ 59.45″ N 87° 40′ 19.25″ W)
• compute distance & azimuths from the given Location

我得到了以下结果：

• 斜边 = 2581
• 轴承 = 135.21
• currentDistanceX = -2562
• currentPixelX = 311.9

想请大家：

1. 确认我的计算结果是否正确。
2. 关于如何计算 currentPixelY（另一个点）？

顺便说一句，我打算用它来计算给定现实生活 LatLng(current) 的位置，并与我的静止图像地图结合起来，将静止图像的左上角和右下角结合到现实生活 LatLng 中。

如果您想查看实际和预期的输出并想轻松了解整个情况。请参考此链接->How to mark the current location into a still image map

Answer 1

这是我使用的实际代码，而不是之前发布的伪代码：

Location upperLeft = new Location("");
upperLeft.setLatitude(41.866514127810355);
upperLeft.setLongitude(-87.6720142364502);
Location lowerRight = new Location("");
lowerRight.setLatitude(41.83397145565242);
lowerRight.setLongitude(-87.62824058532715);
Location current = new Location("");
current.setLatitude(41.850033);
current.setLongitude(-87.65005229999997);
double hypotenuse = upperLeft.distanceTo(current);
double bearing = upperLeft.bearingTo(current);
double currentDistanceX = Math.cos(bearing * Math.PI / 180.0) * hypotenuse;
//                     "percentage to mark the position"
double totalHypotenuse = upperLeft.distanceTo(lowerRight);
double totalDistanceX = totalHypotenuse * Math.cos(upperLeft.bearingTo(lowerRight) * Math.PI / 180.0);
double currentPixelX = currentDistanceX / totalDistanceX * 512;

System.out.println(currentPixelX); // 259.3345493341548

您计算出来的答案看起来有点不对劲。 要计算 Y 更改复制所有 X 标记的计算和变量以使用 Math.sin() 而不是 Math.cos()。