基于PHP的三角定位算法代码
时间: 2023-07-26 22:08:18 浏览: 40
以下是基于PHP的三角定位算法代码:
```php
function triangulate($lat1, $lon1, $lat2, $lon2, $lat3, $lon3) {
// Convert degrees to radians
$rLat1 = deg2rad($lat1);
$rLon1 = deg2rad($lon1);
$rLat2 = deg2rad($lat2);
$rLon2 = deg2rad($lon2);
$rLat3 = deg2rad($lat3);
$rLon3 = deg2rad($lon3);
// Calculate distances between points
$d12 = 2 * asin(sqrt(pow(sin(($rLat1 - $rLat2) / 2), 2) + cos($rLat1) * cos($rLat2) * pow(sin(($rLon1 - $rLon2) / 2), 2))));
$d13 = 2 * asin(sqrt(pow(sin(($rLat1 - $rLat3) / 2), 2) + cos($rLat1) * cos($rLat3) * pow(sin(($rLon1 - $rLon3) / 2), 2))));
$d23 = 2 * asin(sqrt(pow(sin(($rLat2 - $rLat3) / 2), 2) + cos($rLat2) * cos($rLat3) * pow(sin(($rLon2 - $rLon3) / 2), 2))));
// Calculate angles between points
$angle1 = acos((cos($d12) - cos($d13) * cos($d23)) / (sin($d13) * sin($d23)));
$angle2 = acos((cos($d23) - cos($d13) * cos($d12)) / (sin($d13) * sin($d12)));
$angle3 = acos((cos($d13) - cos($d12) * cos($d23)) / (sin($d12) * sin($d23)));
// Calculate area of triangle
$s = ($d12 + $d23 + $d13) / 2;
$area = sqrt($s * ($s - $d12) * ($s - $d23) * ($s - $d13));
// Calculate radius of circumscribed circle
$radius = ($d12 * $d23 * $d13) / (4 * $area);
// Calculate center of circumscribed circle
$A = array($lat1, $lon1);
$B = array($lat2, $lon2);
$C = array($lat3, $lon3);
$AB = array(($A[0] + $B[0]) / 2, ($A[1] + $B[1]) / 2);
$BC = array(($B[0] + $C[0]) / 2, ($B[1] + $C[1]) / 2);
$CA = array(($C[0] + $A[0]) / 2, ($C[1] + $A[1]) / 2);
$circumcenter = intersect($AB, slope($AB, $rLat1, $rLon1), $BC, slope($BC, $rLat2, $rLon2));
// Return latitude, longitude, and radius in an array
return array(rad2deg($circumcenter[0]), rad2deg($circumcenter[1]), $radius);
}
function slope($point, $lat, $lon) {
if ($lat == $point[0]) {
return INF;
} else {
return ($lon - $point[1]) / ($lat - $point[0]);
}
}
function intersect($line1, $slope1, $line2, $slope2) {
if ($slope1 == INF) {
$lat = $line1[0];
$lon = $slope2 * ($lat - $line2[0]) + $line2[1];
} else if ($slope2 == INF) {
$lat = $line2[0];
$lon = $slope1 * ($lat - $line1[0]) + $line1[1];
} else {
$lat = (($slope1 * $line1[0] - $line1[1]) - ($slope2 * $line2[0] - $line2[1])) / ($slope1 - $slope2);
$lon = $slope1 * ($lat - $line1[0]) + $line1[1];
}
return array($lat, $lon);
}
```
该代码实现了三角定位算法,并返回了以该三角形的外接圆为圆心的经度和纬度,以及半径。请注意,该代码假定地球是一个完美的球体,因此其结果可能会因实际地球形状而略有误差。