通过ajax对位置进行排序

Question

I have a JSON object of latitude and longitude locations. I want to list them in the order they are closest to my current lat and long. Is there a way to query using AJAX to get an array of locations in the order of their proximity to my current location. If not, what the best approach I can use.

Answer 1

You can enumerate yours array of coordinates with this function (from this answer):

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)
}

Or you can divide yours coordinates array per sector like:

if lat1 is greater than 70.000 and lesser than 75.000 then this is sector A and so on.

Finally, when you have these sectors you can search in specific one to avoid long calculations.