Hello. Thanks for mapping.
You did a great job on this task, however, you often mapped both the front side and the roof as a building.
You know how to map multi story buildings, I have seen, but this method is also to be used at buildings where you see both a sidewall and the roof. 

Check here how high buildings ought to be mapped.

https://docs.google.com/document/d/1z7uDwYm4oNmlexHIhJxGCjPpNhCQAgRia5aEJr_4MwM/edit?usp=sharing

Or check this footage:
https://drive.google.com/file/d/13RTwH7sChRWrG5bIjysF2ripBgh3F5l4/view?usp=drive_links
Best regards and keep mapping
