
Hello. Thanks for mapping on this difficult task.
About mapping of multy- story apartment blocks or high buildings

Mapping of tall (multi-story) buildings differs from standard buildings. Because the imagery is taken at an angle, you will see both the rooflines and also the side of a building. 
How do you map such a building?
Map over the rooflines and lastly slide the mapped building to the footprint.
Please adjust wrong positioned buildings as well
This video shows how that is done.

https://drive.google.com/file/d/1V5-bADsYiffCD9bo6l64YOdTvmKqMGry/view?usp=share_link

And.... don't forget to square each rectangular building.

Best regards and keep mapping
