Check if coordinates have the same ellipsoid.
| public static checkCoordinatesEllipsoid ( League\Geotools\Coordinate\CoordinateInterface $a, League\Geotools\Coordinate\CoordinateInterface $b ) | ||
| $a | League\Geotools\Coordinate\CoordinateInterface | A coordinate. |
| $b | League\Geotools\Coordinate\CoordinateInterface | A coordinate. |
/**
* Returns the half-way point / coordinate along a great circle
* path between the origin and the destination coordinates.
*
* @return CoordinateInterface
*/
public function middle()
{
Ellipsoid::checkCoordinatesEllipsoid($this->from, $this->to);
$latA = deg2rad($this->from->getLatitude());
$lngA = deg2rad($this->from->getLongitude());
$latB = deg2rad($this->to->getLatitude());
$lngB = deg2rad($this->to->getLongitude());
$bx = cos($latB) * cos($lngB - $lngA);
$by = cos($latB) * sin($lngB - $lngA);
$lat3 = rad2deg(atan2(sin($latA) + sin($latB), sqrt((cos($latA) + $bx) * (cos($latA) + $bx) + $by * $by)));
$lng3 = rad2deg($lngA + atan2($by, cos($latA) + $bx));
return new Coordinate(array($lat3, $lng3), $this->from->getEllipsoid());
}
/**
* Returns geodetic distance between between two coordinates using Vincenty inverse
* formula for ellipsoids which is accurate to within 0.5mm.
* @see http://www.movable-type.co.uk/scripts/latlong-vincenty.html
*
* @return double The distance in meters
*/
public function vincenty()
{
Ellipsoid::checkCoordinatesEllipsoid($this->from, $this->to);
$a = $this->from->getEllipsoid()->getA();
$b = $this->from->getEllipsoid()->getB();
$f = 1 / $this->from->getEllipsoid()->getInvF();
$lL = deg2rad($this->to->getLongitude() - $this->from->getLongitude());
$u1 = atan((1 - $f) * tan(deg2rad($this->from->getLatitude())));
$u2 = atan((1 - $f) * tan(deg2rad($this->to->getLatitude())));
$sinU1 = sin($u1);
$cosU1 = cos($u1);
$sinU2 = sin($u2);
$cosU2 = cos($u2);
$lambda = $lL;
$iterLimit = 100;
do {
$sinLambda = sin($lambda);
$cosLambda = cos($lambda);
$sinSigma = sqrt($cosU2 * $sinLambda * ($cosU2 * $sinLambda) + ($cosU1 * $sinU2 - $sinU1 * $cosU2 * $cosLambda) * ($cosU1 * $sinU2 - $sinU1 * $cosU2 * $cosLambda));
if (0.0 === $sinSigma) {
return 0.0;
// co-incident points
}
$cosSigma = $sinU1 * $sinU2 + $cosU1 * $cosU2 * $cosLambda;
$sigma = atan2($sinSigma, $cosSigma);
$sinAlpha = $cosU1 * $cosU2 * $sinLambda / $sinSigma;
$cosSqAlpha = 1 - $sinAlpha * $sinAlpha;
if ($cosSqAlpha != 0.0) {
$cos2SigmaM = $cosSigma - 2 * $sinU1 * $sinU2 / $cosSqAlpha;
} else {
$cos2SigmaM = 0.0;
}
$cC = $f / 16 * $cosSqAlpha * (4 + $f * (4 - 3 * $cosSqAlpha));
$lambdaP = $lambda;
$lambda = $lL + (1 - $cC) * $f * $sinAlpha * ($sigma + $cC * $sinSigma * ($cos2SigmaM + $cC * $cosSigma * (-1 + 2 * $cos2SigmaM * $cos2SigmaM)));
} while (abs($lambda - $lambdaP) > 1.0E-12 && --$iterLimit > 0);
// @codeCoverageIgnoreStart
if (0 === $iterLimit) {
throw new NotConvergingException('Vincenty formula failed to converge !');
}
// @codeCoverageIgnoreEnd
$uSq = $cosSqAlpha * ($a * $a - $b * $b) / ($b * $b);
$aA = 1 + $uSq / 16384 * (4096 + $uSq * (-768 + $uSq * (320 - 175 * $uSq)));
$bB = $uSq / 1024 * (256 + $uSq * (-128 + $uSq * (74 - 47 * $uSq)));
$deltaSigma = $bB * $sinSigma * ($cos2SigmaM + $bB / 4 * ($cosSigma * (-1 + 2 * $cos2SigmaM * $cos2SigmaM) - $bB / 6 * $cos2SigmaM * (-3 + 4 * $sinSigma * $sinSigma) * (-3 + 4 * $cos2SigmaM * $cos2SigmaM)));
$s = $b * $aA * ($sigma - $deltaSigma);
return $this->convertToUserUnit($s);
}
