从坐标到坐标的确定过程

Question

我有两个点（纬度1，经度1）和（纬度2，经度2）。我如何在PHP中确定需要从点1到点2进行的过程？

的做法是北，南，东，或西这很可能会从度转换？

谢谢！

Answer 1

// Function: latlon_bearing_great_circle 
// Desc: This function calculates the initial bearing you need to travel 
// from Point A to Point B, along a great arc. Repeated calls to this 
// could calculate the bearing at each step of the way. 
function latlon_bearing_great_circle($lat_a, $lon_a, $lat_b, $lon_b) { 
// Convert our degrees to radians: 
list($lat1, $lon1, $lat2, $lon2) = 
    _deg2rad_multi($lat_a, $lon_a, $lat_b, $lon_b); 

// Run the formula and store the answer (in radians) 
$rads = atan2(
     sin($lon2 - $lon1) * cos($lat2), 
     (cos($lat1) * sin($lat2)) - 
       (sin($lat1) * cos($lat2) * cos($lon2 - $lon1))); 

// Convert this back to degrees to use with a compass 
$degrees = rad2deg($rads); 

// If negative subtract it from 360 to get the bearing we are used to. 
$degrees = ($degrees < 0) ? 360 + $degrees : $degrees; 

return $degrees; 
} 

// Function: _deg2rad_multi 
// Desc: A quick helper function. Many of these functions have to convert 
// a value from degrees to radians in order to perform math on them. 
function _deg2rad_multi() { 
    // Grab all the arguments as an array & apply deg2rad to each element 
    $arguments = func_get_args(); 
    return array_map('deg2rad', $arguments); 
} 

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