Where did I go wrong with Haversine calculation in php? -


i have 3 methods looks same result different...

class geocalculations {      const earth_radius = 6371000;      public function degtorad($deg)     {         return $deg * pi() / 180;     }      public function haversinedistance($lat_long_1, $lat_long_2) {         $lat_1 = $this->degtorad($lat_long_1->lat);         $lng_1 = $this->degtorad($lat_long_1->lng);         $lat_2 = $this->degtorad($lat_long_2->lat);         $lng_2 = $this->degtorad($lat_long_2->lng);          $d_lat = $lat_2 - $lat_1;         $d_lng = $lng_2 - $lng_2;          echo "-----------------\n";         var_dump($lat_1);         var_dump($lng_1);         var_dump($lat_2);         var_dump($lng_2);         var_dump($d_lat);         var_dump($d_lng);         echo "-----------------\n";          $cord_length = pow(sin($d_lat / 2), 2) + cos($lat_1) * cos($lat_2) * pow(sin($d_lng / 2), 2);         $central_angle = 2 * atan2(sqrt($cord_length), sqrt(1 - $cord_length));          return self::earth_radius * $central_angle;     }      public function haversinedistance2($lat_long_1, $lat_long_2)     {         $lat_1 = deg2rad($lat_long_1->lat);         $lng_1 = deg2rad($lat_long_1->lng);         $lat_2 = deg2rad($lat_long_2->lat);         $lng_2 = deg2rad($lat_long_2->lng);          $d_lat = $lat_2 - $lat_1;         $d_lng = $lng_2 - $lng_2;          echo "-----------------\n";         var_dump($lat_1);         var_dump($lng_1);         var_dump($lat_2);         var_dump($lng_2);         var_dump($d_lat);         var_dump($d_lng);         echo "-----------------\n";          $angle = 2 * asin(sqrt(pow(sin($d_lat / 2), 2) + cos($lat_1) * cos($lat_2) * pow(sin($d_lng / 2), 2)));          return $angle * self::earth_radius;     }      public function haversinedistance3($lat_long_1, $lat_long_2)     {         $latfrom = deg2rad($lat_long_1->lat);         $lonfrom = deg2rad($lat_long_1->lng);         $latto = deg2rad($lat_long_2->lat);         $lonto = deg2rad($lat_long_2->lng);          $latdelta = $latto - $latfrom;         $londelta = $lonto - $lonfrom;          echo "-----------------\n";         var_dump($latfrom);         var_dump($lonfrom);         var_dump($latto);         var_dump($lonto);         var_dump($latdelta);         var_dump($londelta);         echo "-----------------\n";          $angle = 2 * asin(sqrt(pow(sin($latdelta / 2), 2) +cos($latfrom) * cos($latto) * pow(sin($londelta / 2), 2)));         return $angle * self::earth_radius;     } }  $new = new geocalculations();  $circle_1 = (object) array('lat' => 36.06228, 'lng' => -79.60886); $circle_2 = (object) array('lat' => 36.10926, 'lng' => -79.54423);  var_dump($new->haversinedistance($circle_1, $circle_2)); var_dump($new->haversinedistance2($circle_1, $circle_2)); var_dump($new->haversinedistance3($circle_1, $circle_2));

it prints:

-----------------
float(0.6294055217761)
float(-1.3894367207592)
float(0.63022547745869)
float(-1.3883087144636)
float(0.00081995568258686)
float(0)
-----------------
float(5223.9376537609)
-----------------
float(0.6294055217761)
float(-1.3894367207592)
float(0.63022547745869)
float(-1.3883087144636)
float(0.00081995568258697)
float(0)
-----------------
float(5223.9376537616)
-----------------
float(0.6294055217761)
float(-1.3894367207592)
float(0.63022547745869)
float(-1.3883087144636)
float(0.00081995568258697)
float(0.0011280062955641)
-----------------
float(7811.4545246093)

the third result correct, can't understand wrong first two?

the first 2 have:

$d_lng = $lng_2 - $lng_2;

rather than:

$d_lng = $lng_2 - $lng_1;

(equivalent line in third example):

$londelta = $lonto - $lonfrom;

Comments

Post a Comment

Popular posts from this blog

java.util.scanner - How to read and add only numbers to array from a text file -

i'm learning java , have question regarding reading file want read numbers file contains strings well. here example of file: 66.56 "3 java 3-43 5-42 2.1 1 and here coding: public class test { public static void main (string [] args){ if (0 < args.length) { file x = new file(args[0]); try{ scanner in = new scanner( new fileinputstream(x)); arraylist<double> test = new arraylist<>(); while(in.hasnext()){ if(in.hasnextdouble()){ double f=in.nextdouble(); test.add(f);} else {in.next();} } catch(ioexception e) { system.err.println("exception during reading: " + e); } } my problem add 66.56,2.1 , 1 doesn't add 3 after "3 or ignores 3-43 , 5-42 can tell me how skip strings , add doubles here? thanks all said 3 ie; "3, 3-43 , 4-42 strings either u read string , split , check number @ " , - or put in space between characters , integers. jvm after compilation tre...
Read more

rewrite - Trouble with Wordpress multiple custom querystrings -

i'm working on adding multiple querystring , doesn't seem work. i've found codes seems work others might i'm missing something. i want like: http://mydomain.com/board/?getyear=2013&getsometext2=sometext to http://mydomain.com/board/2013/sometext/ i added code below functions.php file. doesn't seem work should though. this works. echoing querystring gets both variable without problem. http://mydomain.com/board/2013/sometext/ but doesn't. tested querystring vis isset() seems nothing being set/get http://mydomain.com/board/2013/ function add_query_vars($vars) { $vars[] = "getyear"; $vars[] = "getsometext2"; return $vars; } add_filter('query_vars', 'add_query_vars'); function add_rewrite_rules($arules) { $anewrules = array('board/([^/]+)/([^/]+)/?$' => 'index.php?pagename=board&getyear=$matches[1]&getsometext2=$matches[2]'); $arules = $a...
Read more