It is unlawful for any person to intrude or squat upon any lot or piece of land within the city without a license or authority from the owner thereof, or to erect or occupy thereon any hut, hovel, shanty or other structure without such license or authority, or to place, erect or occupy within the bounds of any street, alley or avenue of the city, any hut, shanty, hovel, or other structure without authority of law or ordinance. (Prior Code, Chapter 14, as amended)