Check if location is inside polygon or not

PointLocation.php

<?php

class PointLocation
{

    public static function pointInPolygon($point, $vertices): string
    {
        if (self::pointOnVertex($point, $vertices) == true) {
            return "vertex";
        }

        $intersections = 0;
        $vertices_count = count($vertices);

        for ($i=1; $i < $vertices_count; $i++) {
            $vertex1 = $vertices[$i-1];
            $vertex2 = $vertices[$i];
            if ($vertex1['lng'] == $vertex2['lng'] && $vertex1['lng'] == $point['lng'] && $point['lat'] > min($vertex1['lat'], $vertex2['lat']) && $point['lat'] < max($vertex1['lat'], $vertex2['lat'])) { // Check if point is on an horizontal polygon boundary
                return "boundary";
            }
            
            if ($point['lng'] > min($vertex1['lng'], $vertex2['lng']) && $point['lng'] <= max($vertex1['lng'], $vertex2['lng']) && $point['lat'] <= max($vertex1['lat'], $vertex2['lat']) && $vertex1['lng'] != $vertex2['lng']) {
                $xinters = ($point['lng'] - $vertex1['lng']) * ($vertex2['lat'] - $vertex1['lat']) / ($vertex2['lng'] - $vertex1['lng']) + $vertex1['lat'];
                
                if ($xinters == $point['lat']) {
                    return "boundary";
                }
                
                if ($vertex1['lat'] == $vertex2['lat'] || $point['lat'] <= $xinters) {
                    $intersections++;
                }
            }
        }

        if ($intersections % 2 != 0) {
            return "inside";
        } else {
            return "outside";
        }
    }

    private static function pointOnVertex($point, $vertices)
    {
        foreach($vertices as $vertex) {
            if ($point == $vertex) {
                return true;
            }
        }

        return false;
    }
}