Any information about the distances from the picture would be fantastic. Also I'd like to discuss the issue if you have some experience. Thank you in advance

What are you asking, how much drift is acceptable?  I think DJI advertises GPS accuracy of around 6' or so, at least I think I read that somewhere.  Mine tends to stay inside of a 1-2' area horizontally and once above 6-8' off the ground holds its altitude very well.  Below 6-8' when outdoors mine will have 1-2' of altitude drift.  When inside and using P-OPTI it holds both extremely well and will even fight against outside forces to keep it's position.  I tested this by using a finger to pull one leg while in optical mode and it moved itself back to it's original hover spot!

Question is ... can I fly beneath bridge and than go under construction. (concrete and metal construction can make some problem with quality of gps signal and also propellers are making some air disturbance. I will show you in the picture.

bridge

Red arrow is location

jorukavi1 Posted at 2015-2-2 12:18
Question is ... can I fly beneath bridge and than go under construction. (concrete and metal constru ...

If you travel under a bridge or construction with concrete and rebar or iron you will loose GPS and will be flying in ATTI mode.  Can you do that?  That is the question.  If so you will have no issues if not I would not attempt it.