如何获得围绕中心坐标和半径的N个坐标

Question

I got a center coordinate and a distance/radius, I need to get N number of coordinates from center using radius, for example how to get 12 coordinates of red dots in following image.

Answer 1

you can use the Great-circle_distance calculation to get the points.

I first calculate the bearings from the center point needed then foreach loop them and pass them to the function.

function destinationPoint($lat, $lng, $brng, $dist) {
    $rad = 6371; // earths mean radius
    $dist = $dist/$rad;  // convert dist to angular distance in radians
    $brng = deg2rad($brng);  // conver to radians 
    $lat1 = deg2rad($lat); 
    $lon1 = deg2rad($lng);

    $lat2 = asin(sin($lat1)*cos($dist) + cos($lat1)*sin($dist)*cos($brng) );
    $lon2 = $lon1 + atan2(sin($brng)*sin($dist)*cos($lat1),cos($dist)-sin($lat1)*sin($lat2));
    $lon2 = fmod($lon2 + 3*M_PI, 2*M_PI) - M_PI;  // normalise to -180..+180º
    $lat2 = rad2deg($lat2);
    $lon2 = rad2deg($lon2);


    echo "lat = ".$lat2."
";
    echo "lon = ".$lon2."

";
}

$lat = 0;
$lng = 0;
$dist = 1; // km
$n = 12;

$bearings = range(0, 360-(360/$n)  , 360/$n); // create array of all bearings needed from $lat/$lng

foreach($bearings as $brng){
    echo $brng ."
";
    destinationPoint($lat, $lng, $brng, $dist);
}

In theroy and depending on how accurate you need it to be, you only need to calculate half the values using the function and then you should be able to calculate the other half with basic calculation.
But if the distance is large (don't know exactly what large means) it may make a difference.

https://3v4l.org/4fI7F