计算地图上两点间的距离

1. class GeoHelper
2. {
3. /**
4. * @param int $lat1
5. * @param int $lon1
6. * @param int $lat2
7. * @param int $lon2
8. * @param string $unit
9. * @return
10. */
11. public static function distance($lat1, $lon1, $lat2, $lon2, $unit = "K")
12. {
13. $theta = $lon1 - $lon2;
14. $dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) + cos(deg2rad($lat1)) * cos(deg2rad
15. ($lat2)) * cos(deg2rad($theta));
16. $dist = acos($dist);
17. $dist = rad2deg($dist);
18. $miles = $dist * 60 * 1.1515;
19. $unit = strtoupper($unit);
21. if ($unit == "K") {
22. return ($miles * 1.609344);
23. } else
24. if ($unit == "N") {
25. return ($miles * 0.8684);
26. } else { //mi
27. return $miles;
28. }
29. }
31. /**
32. *
33. * @param string $address
34. * @param string $apikey
35. * @return array [1]:lat [0]:lng
36. */
37. public static function getLatLng($address, $apikey)
38. {
39. $find = array("\n", "\r", " ");
40. $replace = array("", "", "+");
41. $address = str_replace($find, $replace, $address);
42. $url = 'http://maps.google.com/maps/geo?q=' . $address . '&key=' . $apikey .
43. '&sensor=false&output=xml&oe=utf8';
44. $response = self::xml2array($url);
45. $coordinates = $response['kml']['Response']['Placemark']['Point']['coordinates'];
46. if (!empty($coordinates)) {
47. $point_array = split(",", $coordinates);
48. return $point_array;
49. }
50. }
51. }

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