Hi, 

I have a questions about how to the distance to the project boundary and mounting height is considered for lighting fixtures mounted on a roof terrace. Is the distance to the project boundary measured in plan , and then the mounting height from the ground level. Meaning that a wall fixture/marker mounted at 0.5 above the floor of the roof terrace will have a mounting height of 19.5mt if the terrace floor is 19mt above the ground? Or how should it be taken into account? 

Thanks in advance,