Is the Bagua geomantic omen based on the whole yard or the main building?

It depends on how big the pattern is. For example, the property right of the whole yard is yours. You should look at the whole yard and determine the location of Bazhai with the gate as the direction.

If you are the owner of a building, look at the door of the building and confirm the location.

If it is the owner of the first floor, look at it as the first floor.

If so, the owner of a unit will look at the door of the unit.

If you only rent one room, look at the door of this room.

I hope it helps you.