例子一:

1. function distance($lat1, $lng1, $lat2, $lng2, $miles = true){
2. $pi80 = M_PI / 180;
3. $lat1 *= $pi80;
4. $lng1 *= $pi80;
5. $lat2 *= $pi80;
6. $lng2 *= $pi80;
7. $r = 6372.797;
8. $dlat = $lat2 - $lat1;
9. $dlng = $lng2 - $lng1;
10. $a = sin($dlat/2)*sin($dlat/2)+cos($lat1)*cos($lat2)*sin($dlng/2)*sin($dlng/2);
11. $c = 2 * atan2(sqrt($a), sqrt(1 - $a));
12. $km = $r * $c;
13. return ($miles ? ($km * 0.621371192) : $km);
14. }

例子二:

1. /**
2. * 计算两个坐标之间的距离(米)
3. * @param float $fP1Lat 起点(纬度)
4. * @param float $fP1Lon 起点(经度)
5. * @param float $fP2Lat 终点(纬度)
6. * @param float $fP2Lon 终点(经度)
7. * @return int
8. */
9. function distanceBetween($fP1Lat, $fP1Lon, $fP2Lat, $fP2Lon){
10. $fEARTH_RADIUS = 6378137;
11. //角度换算成弧度
12. $fRadLon1 = deg2rad($fP1Lon);
13. $fRadLon2 = deg2rad($fP2Lon);
14. $fRadLat1 = deg2rad($fP1Lat);
15. $fRadLat2 = deg2rad($fP2Lat);
16. //计算经纬度的差值
17. $fD1 = abs($fRadLat1 - $fRadLat2);
18. $fD2 = abs($fRadLon1 - $fRadLon2);
19. //距离计算
20. $fP = pow(sin($fD1/2), 2) +
21. cos($fRadLat1) * cos($fRadLat2) * pow(sin($fD2/2), 2);
22. return intval($fEARTH_RADIUS * 2 * asin(sqrt($fP)) + 0.5);
23. }
24. /**
25. * 百度坐标系转换成标准GPS坐系
26. * @param float $lnglat 坐标(如:106.426, 29.553404)
27. * @return string 转换后的标准GPS值:
28. */
29. function BD09LLtoWGS84($fLng, $fLat){ // 经度,纬度
30. $lnglat = explode(',', $lnglat);
31. list($x,$y) = $lnglat;
32. $Baidu_Server = "http://api.map.baidu.com/ag/coord/convert?from=0&to=4&x={$x}&y={$y}";
33. $result = @file_get_contents($Baidu_Server);
34. $json = json_decode($result);
35. if($json->error == 0){
36. $bx = base64_decode($json->x);
37. $by = base64_decode($json->y);
38. $GPS_x = 2 * $x - $bx;
39. $GPS_y = 2 * $y - $by;
40. return $GPS_x.','.$GPS_y;//经度,纬度
41. }else
42. return $lnglat;
43. }