It is at first a reference to the cadastral plan filed in the land register. In the case of a horizontal co-ownership, the cadastral plan will divide the land, from the zenith (highest point) to the nadir (lower point). The declaration of co-ownership of a horizontal co-ownership will supervise the management of land and common facilities to the private portions. An example of horizontal co-ownership would be the one of townhouses where each of the townhouses would be a private portion and the space which surrounds them (front and back yards, green spaces, parking, landscaping) would constitute the common portions.