The whole idea of Eminent domain, in theory, is based upon the idea that governments can intervene to protect the greater good. As Kant discusses, positive right means that people are imposed with a duty. Therefore, not only is the "idea" of eminent domain one of moral duty, but it is applicable to what Kant would call positive rights. However, it is not really the case, when we look at how eminent domain is applied. Governments take land from people, but is it really for the benefit of the public? Stop & Shops? Airports? These are merely private businesses, which the government sells the land they take to. On the flip side, if Eminent domain were applied like it was probably intended to, it could work out ok. For example, if someone's property were near a dam that needed expanding, a damn that the town needed (whether it was about to collapse, or it provided for the town economically), this could be reasonable justification.

As for the idea of land ownership, doesn't owning land generally give you a sense of security? Think about all the homeless who get arrested for loitering. Your land means you have a place where you can guarantee you're welcome. Your land means that there's somewhere you can do anything (within legal boundaries) you want. Your land means you can build, sleep, eat, and live somewhere without being thrown out.