original_string: function geoGetDistance($lat1,$lon1,$lat2,$lon2,$unit='M') {
          
        // calculate miles
        $M =  69.09 * rad2deg(acos(sin(deg2rad($lat1)) * sin(deg2rad($lat2)) +  cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($lon1 - $lon2)))); 
  
        switch(strtoupper($unit))
        {
          case 'K':
            // kilometers
            return $M * 1.609344;
            break;
          case 'N':
            // nautical miles
            return $M * 0.868976242;
            break;
          case 'F':
            // feet
            return $M * 5280;
            break;            
          case 'I':
            // inches
            return $M * 63360;
            break;            
          case 'M':
          default:
            // miles
            return $M;
            break;
        }
        
      }
code: function geoGetDistance($lat1,$lon1,$lat2,$lon2,$unit='M') {
          
        // calculate miles
        $M =  69.09 * rad2deg(acos(sin(deg2rad($lat1)) * sin(deg2rad($lat2)) +  cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($lon1 - $lon2)))); 
  
        switch(strtoupper($unit))
        {
          case 'K':
            // kilometers
            return $M * 1.609344;
            break;
          case 'N':
            // nautical miles
            return $M * 0.868976242;
            break;
          case 'F':
            // feet
            return $M * 5280;
            break;            
          case 'I':
            // inches
            return $M * 63360;
            break;            
          case 'M':
          default:
            // miles
            return $M;
            break;
        }
        
      }
code_tokens: function geoGetDistance ( $ lat1 , $ lon1 , $ lat2 , $ lon2 , $ unit = 'M' ) { // calculate miles $ M = 69.09 * rad2deg ( acos ( sin ( deg2rad ( $ lat1 ) ) * sin ( deg2rad ( $ lat2 ) ) + cos ( deg2rad ( $ lat1 ) ) * cos ( deg2rad ( $ lat2 ) ) * cos ( deg2rad ( $ lon1 - $ lon2 ) ) ) ) ; switch ( strtoupper ( $ unit ) ) { case 'K' : // kilometers return $ M * 1.609344 ; break ; case 'N' : // nautical miles return $ M * 0.868976242 ; break ; case 'F' : // feet return $ M * 5280 ; break ; case 'I' : // inches return $ M * 63360 ; break ; case 'M' : default : // miles return $ M ; break ; } }
docstring: get distance between to geocoords using great circle distance formula
  
  @param float $lat1
  @param float $lat2
  @param float $lon1
  @param float $lon2
  @param float $unit   M=miles, K=kilometers, N=nautical miles, I=inches, F=feet
  @return float
docstring_tokens: get distance between to geocoords using great circle distance formula