Question

我通过此链接how-to-display-a-map-still-image-file-with-a-moving-current-location

从@DanS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：

目前：41.850033，-87.65005229999997
upperLeft：41.866514127810355，-87.6720142364502
lowerRight：41.83397145565242，-87.62824058532715
mapWidth：512 x 512 px

以下是位置，斜边（距离），方位（方位角）的在线计算器

我得到了结果：

hypotenuse = 2581
方位= 135.21
currentDistanceX = -2562
currentPixelX = 311.9

想请你们：

确认我的计算结果是否正确。
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真实生活LatLng（当前）的位置，用我的静止图像贴图将静止图像的upperLeft和lowerRight角粘合到现实生活中LatLng。

如果你想看到实际的＆amp;期望的输出，并希望轻松了解整个画面。请参阅此链接 - ＆gt; How to mark the current location into a still image map

Answer 1

这是我正在使用的实际代码，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

您的计算答案看起来有些偏差。要计算Y更改，请将所有X标记的计算和变量复制为使用Math.sin()而不是Math.cos()。

如何计算斜边和轴承

1 个答案: