gistfile1.php

foreach (City::search("{$x} > x_min AND {$x} < x_max AND {$y} > y_min AND {$y} < y_max") as $city) {
    $left_node = $right_node = 0;
    $lastx = $lasty = null;

    foreach ($city->bounds as $bound) {
        if (is_null($lastx)) {
            $lastx = $bound->x;
            $lasty = $bound->y;
            continue;
        }

        if (($bound->y >= $y and $y >= $lasty) or ($lasty >= $y and $y >= $bound->y)) {
            if ($x >= $bound->x and $x >= $lastx) {
                $right_node ++;
            } elseif ($x <= $bound->x and $x <= $lastx) {
                $left_node ++;
            } else {
                $deltax = $bound->x - $lastx;
                $deltay = $bound->y - $lasty;
                $tempx = ($y - $lasty) * $deltax / $deltay + $lastx;
                if ($x >= $deltax) {
                    $right_node ++;
                } else {
                    $left_node ++;
                }
            }
        }
        $lastx = $bound->x;
        $lasty = $bound->y;
    }

    if ($left_node % 2 == 1 && $right_node % 2 == 1){
        echo $city->city . ' ' . $city->sub_city;
    }
}