Java - 從位置集合中獲取基於距離的位置

Question

我有一組集合中的對象具有作爲屬性的經度和地位。現在我想要得到所有那些距離一定距離的物體，例如輸入經度和緯度的50英里半徑。我應該使用什麼樣的數據結構和搜索所有這些點的算法。

Answer 1

藉助下面的代碼解決了我的問題。

package com.csc.banking.celeriti.cache.srv.utils; 

    public class GeoDistanceCalculator { 


     private static double distance(double lat1, double lon1, double lat2, double lon2, char unit) { 
      double theta = lon1 - lon2; 
      double dist = Math.sin(deg2rad(lat1)) * Math.sin(deg2rad(lat2)) + Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) * Math.cos(deg2rad(theta)); 
      dist = Math.acos(dist); 
      dist = rad2deg(dist); 
      dist = dist * 60 * 1.1515; 
      if (unit == 'K') { 
      dist = dist * 1.609344; 
      } else if (unit == 'N') { 
      dist = dist * 0.8684; 
      } 
      return (dist); 
     } 


     public static double distanceKms(double lat1, double lon1, double lat2, double lon2){ 
      return distance(lat1, lon1, lat2, lon2, 'K'); 
     } 

     public static double distanceNauticalMiles(double lat1, double lon1, double lat2, double lon2){ 
      return distance(lat1, lon1, lat2, lon2, 'N'); 
     } 

     public static double distanceMiles(double lat1, double lon1, double lat2, double lon2){ 
      return distance(lat1, lon1, lat2, lon2, 'M'); 
     } 

     private static double deg2rad(double deg) { 
      return (deg * Math.PI/180.0); 
     } 

     private static double rad2deg(double rad) { 
      return (rad * 180/Math.PI); 
     } 

     public static void main(String[] args) { 
      System.out.println(distance(32.9697, -96.80322, 29.46786, -98.53506, 'M') + " Miles\n"); 
      System.out.println(distance(32.9697, -96.80322, 29.46786, -98.53506, 'K') + " Kilometers\n"); 
      System.out.println(distance(32.9697, -96.80322, 29.46786, -98.53506, 'N') + " Nautical Miles\n"); 

      System.out.println(distance(28.6207641, 77.36392920000003, 28.6314512, 77.21666720000007, 'K') + " Connaught Place Delhi to Noida 62\n"); 


     } 

    }