If you buy a whole plot (single plot), you do not need to survey the property you are going to purchase - even not for the registration in the Land Registry. The name of the cadastral municipality, the plot number and an EZ number are basically sufficient.
If you wish to buy or sell only a part of plot, you definitely need our help. Those sudbdivisions can only be done by state-authorized and certificated civil engineers. (§1 property subdivision law)
Nevertheless, it is always beneficial for you to get in contact with a state-authorized, certificated civil engineer (IKV). With his help you have a proof that
It is definitely recommended to contact an IKV, when you buy or sell a plot in the rural area (maybe the property boundaries have not been determined so far) or if you plan to buy or sell some land where the squaremeter price is pretty high.