It is not a problem to multiply usd bid price and volume of btc in each bid order.

But as nimnul explained, that simple multiplication will not get meaningful number.

The problem is that not all bid orders have meaningful, as nimnul stated a "real", price. e.g. if someone places a bid order to buy 1000 000 000 btc for 1 USD, in other words buyer expects to buy 1bn btc at 0,000000001 usd/btc. does this price make sence for your analyzes? Such order will be never executed.
Thus such orders represents spam, not real , fake data in the orderbook.

In other words this one fake order will make bids line several orders higher than asks line. 1bn btc on bids side which are not existent and 100k btc on the asks. This really does not make sence. Can you agree?

There are a lot of such orders, and their combined volume just obscurs the true picture.

If we exclude those fake orders we will see the true picture.

It this clear?

So the question is how to tell which orders have to be excluded and which not?

There is no common agreement on which order have to be counted as meaningful and which is not.

So how to find this common filtering creteria is the main question.

Do you have any ideas on how can we solve it?