Estoy usando una verificación de punto en el polígono en php, pero recibo errores importantes, ya que en los puntos que no están en el polígono aparecen como dentro.

Mis funciones básicas se detallan a continuación (que se encuentran aquí, modificadas de una clase a una función simple:http: //www.assemblysys.com/dataServices/php_pointinpolygon.ph). ¿Lo único que se me ocurre es algún tipo de error de redondeo en alguna parte?

omo ejemplo, estoy tratando de determinar si un punto está en Central Park, un cuadrado simple, pero obtengo puntos positivos de puntos fuera del parque.

Gracias por cualquier idea,

-R

$central_park = array('40.768109,-73.981885', '40.800636,-73.958067', '40.796900,-73.949184', '40.764307,-73.972959');

$test_points = array('40.7546755,-73.9758343', '40.764405,-73.973951', '40.7594219,-73.9733896', '40.768137896318315,-73.9814176061', '40.7982394,-73.9523718', '40.685135,-73.973562', '40.7777062,-73.9632719', '40.764109,-73.975948', '40.758908,-73.9813128', '40.7982782,-73.9525028', '40.7463886,-73.9817654', '40.7514592,-73.9760405', '40.7514592,-73.9760155', '40.7514592,-73.9759905', '40.7995079,-73.955431', '40.7604354,-73.9758778', '40.7642878,-73.9730075', '40.7655335,-73.9800484', '40.7521678,-73.9777978', '40.7521678,-73.9777728')

function pointStringToCoordinates($pointString) {
    $coordinates = explode(",", $pointString);
    return array("x" => trim($coordinates[0]), "y" => trim($coordinates[1]));
}

function isWithinBoundary($point,$polygon){

    $point = pointStringToCoordinates($point);

    $vertices = array();

    foreach ($polygon as $vertex) {
        $vertices[] = pointStringToCoordinates($vertex); 
    }

    // Check if the point is inside the polygon or on the boundary
    $intersections = 0; 
    $vertices_count = count($vertices);

    for ($i=1; $i < $vertices_count; $i++) {

        $vertex1 = $vertices[$i-1]; 
        $vertex2 = $vertices[$i];

        if ($vertex1['y'] == $vertex2['y'] and $vertex1['y'] == $point['y'] and $point['x'] > min($vertex1['x'], $vertex2['x']) and $point['x'] < max($vertex1['x'], $vertex2['x'])) { // Check if point is on an horizontal polygon boundary
            $result = TRUE;
        }

        if ($point['y'] > min($vertex1['y'], $vertex2['y']) and $point['y'] <= max($vertex1['y'], $vertex2['y']) and $point['x'] <= max($vertex1['x'], $vertex2['x']) and $vertex1['y'] != $vertex2['y']) { 

            $xinters = ($point['y'] - $vertex1['y']) * ($vertex2['x'] - $vertex1['x']) / ($vertex2['y'] - $vertex1['y']) + $vertex1['x']; 

            if ($xinters == $point['x']) { // Check if point is on the polygon boundary (other than horizontal)
                $result = TRUE;
            }

            if ($vertex1['x'] == $vertex2['x'] || $point['x'] <= $xinters) {
                $intersections++; 
            }

        } 

    }

    // If the number of edges we passed through is even, then it's in the polygon. 
    if ($intersections % 2 != 0) {
        $result = TRUE;
    } else {
        $result = FALSE;
    }

    return $result;

}