Land expected for development, who sets the boundary here?

Hello everyone,

I own an area of about 20,000 sqm on the outskirts of a small town in eastern Germany. The area consists of a smaller garden plot/pasture (green) and a community garden complex (orange) (see graphic below). The lower part of the area is designated as land expected to be developed in the land use plan. In the illustration, this would be the part below the dashed line.

Now I have a prospective buyer who wants to purchase and develop this land expected to be developed. Therefore, the big question now is exactly where the boundary of the land expected to be developed runs.

Of course, you can agree on an area value in the purchase contract and after the survey is completed, any overpaid or underpaid amount can be balanced out. That would be no problem. But for me, the exact boundary is relevant for two reasons:

First, some leased plots in the community garden complex may have to be cleared or relocated. (There is consensus with the association, the complex is mostly vacant).

And second, I of course have an interest in selling as much as possible. So to move the boundary upwards as far as possible.

Although the land use plan of the city shows both the building land and the land expected to be developed, the map is quite rough, and even the line thickness (dashed line in the second illustration) is practically several meters thick in reality. And as far as I know, the land use plan is more intended as a guideline and does not show the exact boundaries precisely, right?

Therefore, I am turning to you in the hope of finding someone who knows how this usually works. Who ultimately decides exactly how far the future building area may extend? Can I already find this out at this point in time so that I can proceed with the termination/relocation of the garden plots?

I am grateful for any help!! Best regards!

Does no one have an idea?

How does something like this usually proceed?
Does the responsible building authority decide on the exact boundary course?
Or the surveyor?

Best regards.

I would assume that the city determines that or at least can give you more precise information about who determines that. As a rule, they usually also have it recorded somewhere "we still have so and so much land designated for construction here and there and over there." Whether that is fully surveyed at that time, or whether that only really happens then with the proper preparation of a development plan or something, no idea...

Why should you get more money for agricultural land with development prospects than for regular land? The fact that it will ever become building land is as uncertain as playing the lottery. The risk that no development plan will be established at the municipal level is still high. I know agricultural land with development prospects that has been waiting forever for conversion. That's why the question: why should anyone pay you more for it?

There is a potential buyer, but I think it's more about the size of the property. However, I assume that before you draw up a purchase contract, the property would first have to be divided into two parcels. Presumably, they would also measure it in the process? But I'm not exactly sure. Alternatively, maybe the buyer is also interested in the entire property including the allotment garden association?

I can't make any sense of the two pictures. Is there no map from the Geoportal where the 20,000 sqm can be seen? In the Geoportal, you can even access the different maps. Then overlay the property boundaries on the land use plan. Ideally, also provide an appropriate aerial photo with the property boundaries marked.

You can only really help if you know the relevant plot numbers.