PHP - Calculate the center point of multiple latitude/longitude coordinate pairs

GetCenterFromDegrees.php

function GetCenterFromDegrees(array $data)
{
		if (!count($data)) {
			return false;
		}

		$numCoords = count($data);

		$X = 0.0;
		$Y = 0.0;
		$Z = 0.0;

		for($i = 0; $i < count($data); $i++){
			$lat = $data[$i][0] * pi() / 180;
			$lon = $data[$i][1] * pi() / 180;

			$a = cos($lat) * cos($lon);
			$b = cos($lat) * sin($lon);
			$c = sin($lat);

			$X += $a;
			$Y += $b;
			$Z += $c;
		}

		$X /= $numCoords;
		$Y /= $numCoords;
		$Z /= $numCoords;

		$lon = atan2($Y, $X);
		$hyp = sqrt($X * $X + $Y * $Y);
		$lat = atan2($Z, $hyp);

		$newX = ($lat * 180 / pi());
		$newY = ($lon * 180 / pi());

		return [$newX, $newY];
}