P owns and operates a ready-mix concrete plant that was constructed in 1954. In 1959, D passed a zoning ordinance permitting ready-mix plants in the area of the city zoned for industrial use but only pursuant to a special use permit. D did not grant a special use permit to the then-owners of this ready-mix plant. The plant was classified as a preexisting nonconforming use because it was within 400 feet of a residential district. In 1973, D eliminated ready-mix and concrete block plants as permitted uses in the city. P purchased the ready-mix plant in 1974 for $260,000. In May 1980, D adopted a new comprehensive plan and put P on notice that the city intended to phase out the plant and rezone the site for commercial or office use or 'as a second choice high-density residential use.' P commenced a declaratory judgment action seeking to invalidate the 1973 zoning ordinance on the ground that it wrongfully eliminated ready-mix plants as permitted uses in industrial zones. The district court declared the ordinance void as applied to P. D appealed. The court concluded that because the plant was not a public nuisance or a nuisance per se, the city could not legislate it out of existence. In 1990, the city adopted a new comprehensive plan, which provides that heavy industrial uses including a concrete ready mix plant and outdoor storage of heavy equipment are to be phased out, and the sites are to be used for high-density residential use. D was to establish an amortization period for individual land uses not permitted in the City. D was to meet with each property owner, review each registration application, and determine a reasonable amortization period for each nonconforming use. The following factors were to be considered: a. Information relating to the structure located on the property; b. Nature of the use; c. Location of the property in relation to surrounding uses; d. Description of the character of and uses in the surrounding neighborhood; e. Cost of the property and improvements to the property; f. Benefit to the public by requiring the termination of the non-conforming use; g. Burden on the property owner by requiring the termination of the non-conforming use; h. The length of time the use has been in existence and the length of time the use has been non-conforming. D held a public hearing P's amortization period with both sides presenting evidence. D determined that P would have 2 years. D had retained an accounting firm and a real estate appraisal firm for its evidence and determined that P had not only recovered its investment but also had earned a return of approximately 560 percent on its investment. P sought a declaration that the D's amortization ordinance violated P's right to due process and equal protection of the laws as well as an unconstitutional taking of P’s property without just compensation.