src/Formatter/Polygon/GeoJSON.php
public function format(Polygon $polygon): string
    {
        if ($polygon->getNumberOfPoints() < 3) {
            throw new InvalidPolygonException('A polygon must consist of at least three points.');
        }

        $points = [];

        /** @var Coordinate $point */
        foreach ($polygon->getPoints() as $point) {
            $points[] = [$point->getLng(), $point->getLat()];
        }

        return json_encode(
            [
                'type' => 'Polygon',
                'coordinates' => [$points],
            ]
        );
    }
public function format(Polygon $polygon): string
    {
        if ($polygon->getNumberOfPoints() < 3) {
            throw new InvalidPolygonException('A polygon must consist of at least three points.');
        }

        $points = [];

        /** @var Coordinate $point */
        foreach ($polygon->getPoints() as $point) {
            $points[] = [$point->getLng(), $point->getLat()];
        }

        return json_encode(
            [
                'type' => 'Polygon',
                'coordinates' => [$points],
            ]
        );
    }
@param Polygon $polygon

@return string

@throws InvalidPolygonException