Eminent Domain
Eminent domain or a "taking" exists when a branch of government takes your property or a portion of your property. When this happens the government is required to compensate you justly. What is just? For what uses or purposes can a government do this?
There are many intersecting areas of law where this can get complicated. How do you value the loss? What about easements? Is a regulation that prevents you from using your property as intended the equivalent of a taking? If so, how do you get the government to revise its regulation or pay you for your loss?
How does one deal with the government agency? Who is responsible?
As you can see, this area of law raises many questions. There are practical considerations as well as constitutional protections to balance in achieving the best result for a property owner's rights in any particular situation.