The legal property line is determined by a licensed surveyor ascertaining it in his or her opinion based upon the legal description of two adjoining properties and then confirmed in a court order if there is a legal dispute on this issue.It is not an issue of the city allowing a property owner to encroach on another person's property but rather one owner allowing this to happen either by mistake or on purpose.Until you have a court order establishing the true property line between your land and the neighbor's, I would deem the most recent survey an indication of where the true dividing line is between the two parcels.