Roof measurements in square meters & aerial photos needed.

I need accurate roof measurements in square meters and accurate aerial photos of each building located inside a specific campus. The name of the campus is called Transnet Esselenpark Campus School of Rail located in 150 Van Huyssteen Ave, Esselen Park, 1619 Kempton Park, Gauteng
I have attached a picture of the front entrance into the campus and the best possible aerial photo I have managed to take from Google Earth showing an inaccurate overview of the campus and all the buildings inside the campus.