如何获得5英里距离内的所有邮政编码

Question

我希望用户输入的邮政编码距离5英里以内的所有邮政编码。

Answer 1

看到你有圆的中心坐标和圆的半径说5英里，现在对于数据库中的每个坐标点，通过应用距离公式检查中心与该点之间的距离，并检查它是否小于半径， 简而言之，

C = point that is the center of the area
P = point we want to check for being inside the area
R = radius of the area

P is inside the area if

||P-C|| <= R

编辑 -

function getDistanceFromLatLonInKm(lat1,lon1,lat2,lon2) {
  var R = 6371; // Radius of the earth in km
  var dLat = deg2rad(lat2-lat1);  // deg2rad below
  var dLon = deg2rad(lon2-lon1); 
  var a = 
    Math.sin(dLat/2) * Math.sin(dLat/2) +
    Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) * 
    Math.sin(dLon/2) * Math.sin(dLon/2)
    ; 
  var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
  var d = R * c; // Distance in km
  return d;
}

function deg2rad(deg) {
  return deg * (Math.PI/180)
}