(1) Just compensation shall be paid upon the removal of any existing sign pursuant to the provisions of any resolution or ordinance of any county, city, or town of the state of Washington by such county, city, or town if:
(a) Such sign was lawfully in existence on May 10, 1971 (the effective date of the Scenic Vistas Act of 1971); or
(b) Such sign was erected subsequent to May 10, 1971 (the effective date of the Scenic Vistas Act of 1971), in compliance with existing state and local law.
(2) Such compensation shall be paid in the same manner as specified in RCW
47.42.102(2) for the following:
(a) The taking from the owner of such sign, display, or device of all right, title, leasehold, and interest in such sign, display, or device; and
(b) The taking from the owner of the real property on which the sign, display, or device is located, of the right to erect and maintain such signs, displays, and devices thereon.