It is the legislature that has the power to determine the necessity of taking property for public use, as well as the amount of property to be taken. Most takings must comport with legislative language that mandates under what circumstances such an action is justified or necessary.
Government Condemnation Power
If a local government deems certain property to be a hazard to the public, e.g. a health or safety risk, it may condemn the property as unfit for human occupancy following formal inspection and assessment. Usually this is accomplished by citation of violations involving local ordinances, building codes, or federal public safety regulations. During the time between condemnation and bringing the property back into conformity with relevant laws, a landowner is generally not entitled to compensation, even though a deprivation of property rights has occurred.
"Excess Condemnation" Actions
A formal court action objecting to the taking of property that is not strictly needed for public use -- or for taking more property than needed for public use -- is generally referred to as an action for "excess condemnation."