检查纬度和经度是否在谷歌地图的圆圈内 [英] Check if a latitude and longitude is within a circle google maps

问题描述

下面是我想要的结果

我想知道的是:

我使用中心点纬度和半径创建了圆.现在我想知道，如何检查(计算)纬度和经度是在该区域的内部还是外部，如果您能给我 Javascript 中的代码示例，我将不胜感激.我使用的是 Google Maps API V3.

I have created the circle using center point lat lang and radius around it. Now I want to know, how to check (calculate) if a latitude and longitude is either inside or outside the area I would appreciate if you can give me code example in Javascript. I'm using Google Maps API V3.

我发现了这个功能，但没有按预期工作:

function arePointsNear(checkPoint, centerPoint) {
    var sw = new google.maps.LatLng(centerPoint.lat() - 0.005, centerPoint.lng() - 0.005);
    var ne = new google.maps.LatLng(centerPoint.lat() + 0.005, centerPoint.lng() + 0.005);
    var bounds = new google.maps.LatLngBounds(sw, ne);
    if (bounds.contains (checkPoint)){
        return true;
    }
    return false;
}

任何帮助都会很棒..提前致谢！！

Any help will be great.. thanks in advance!!

推荐答案

对于如此短的距离，并且当精度不必精确到厘米时，您可以将地球表面视为平坦的.计算中心点纬度处度数到公里的换算，则勾股定理可得用于获取距离:

For such short distances, and when the accuracy doesn't have to be exact to the centimeter, you can treat the surface of the earth as flat. Calculate a conversion from degrees to kilometers at the latitude of the center point, then the Pythagorean theorem can be used to get the distance:

function arePointsNear(checkPoint, centerPoint, km) {
  var ky = 40000 / 360;
  var kx = Math.cos(Math.PI * centerPoint.lat / 180.0) * ky;
  var dx = Math.abs(centerPoint.lng - checkPoint.lng) * kx;
  var dy = Math.abs(centerPoint.lat - checkPoint.lat) * ky;
  return Math.sqrt(dx * dx + dy * dy) <= km;
}

演示:http://jsfiddle.net/Guffa/57gQa/

注意:如果您传递的是 0/360 经度，则代码不会考虑在内.如果是这种情况，您必须先对经度进行归一化.

Note: The code doesn't take into consideration if you are passing the 0/360 longitude. If that is the case, you would have to normalize the longitudes first.

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