What Percentage of the Field Goes When It Is Opened to Development?

Land is one of the most valuable tools in real estate investment.
In fact, land is much more attractive for investment. The main reason for this is that the m² price is lower than the land and its value increases over time with the possibility of development.
Vineyard, garden and field are the main types of land.
When zoning comes to a place with land status, not all of the available area remains with the parcel owner.
A certain part of the relevant parcel goes to the public abandonment area. Road, park,..
When a place with land status changes to land status, a maximum and general amount of 45% is reduced.
To give an example, a land of 1,000 m² decreases to 550 m² after zoning.
Of course, the value of a place that has been developed increases significantly.