When talking about the ownership of land, one deals with property law. Property law is concerned with questions such as how you describe a boundary, what's the scope of a particular easement, and does a mechanic's lien gain priority over an unrecorded mortgage? There are rules here which haven't changed much since Blackstone wrote them down. Thus law can be a set of rules that resemble the axioms of geometry and, often enough, the image of the lawyer as pettifogging nitpicker is an apt one.