检查纬度和经度是否在圆圈Google地图内 [英] Check if a latitude and longitude is within a circle google maps

问题描述

下面是我期待的结果

我想知道的是：

我已经使用中心点纬度和半径创建了圆圈。现在我想知道，如何检查（计算）经纬度是在区域内还是区域之外，如果您可以在Javascript中给我代码示例，我将不胜感激。我使用的是Google Maps API V3。

我发现了这个功能，但没有像我预期的那样工作：

 函数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; 
} 
返回false; 
} 
  

任何帮助都会很棒..提前致谢!!

解决方案

对于这样短的距离，当精度不必精确到厘米时，可以将地球表面视为平面。计算中心点纬度处从度数到公里的转换，然后 Pythagoran定理可以用于获取dinstance：

$ p $ 函数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：代码不考虑考虑你是否通过0/360经度。如果是这样的话，你首先必须正常化经度。

Below is the desired result, which I'm looking for

What I would like to know is:

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.

I found this function but not working as expected for me:

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;
}

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

解决方案

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 Pythagoran theorem can be used to get the dinstance:

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;
}

Demo: http://jsfiddle.net/Guffa/57gQa/

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

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