Item 2: Land survey; Land survey is important because it allows the builder/engineer understand the following information;
1. Understand the relative height of the site with respect to an ordinance benched mark already in existence
2. It enable the building line of the building to be known
3. It will also help to control the drainage of the building and the site in future.

Most building owners don't do this item 2 because fear of cost or ignorant but it reality, it is relatively cheap to do.
For a small building project, it cost about N10,000 to rent a theodolite or N20,000 to rent a Total stations for one day and the operator/surveyor/engineer is paid around N10,000 making a sum of N30,000 ( maximum).