It is unlawful for any person to enter upon the property of another or into an area or structure on that property, whether the property, area or structure is public or private, when entrance is plainly forbidden by signs or otherwise, or when the property, area or structure is enclosed, except when entrance is in the line of duty, or with the expressed or tacit consent of the owner or person in charge, or otherwise by authority of law or ordinance. (2001 Code § 133.09)