Trading volume of Bitcoin – Bitcoin Stack Exchange

I was trying to see how the trading volume and market cap of Bitcoin are compared to each other. I quickly found https://coinmarketcap.com/ and similar sites which tell the same story:

Bitcoin has a market cap in the order of magnitude of 18.5M btc (currently about 500B USD) and a trading volume around 1.6M btc (50B USD).

I guess that the market cap (measured in btc) is pretty much spot on, as I am not aware of coins that stay invisible to the chain.

However, I am still curious to get some feeling for the actual volume of Bitcoin that changes hands. I suppose one could categorize this in 3 buckets:

  1. Transactions that hit the chain (presumably the volume of this is 1.6B)
  2. Coins transferred via well known places, perhaps exchanges
  3. Coins transferred via other methods, perhaps giving someone your wallet

Now my question:
#What is the estimated trading volume of Bitcoin?

My first thoughts:

  • If my above logic is correct, we could add up exchange volumes to the chain volumes
  • Perhaps there is some insight in the proportion of the three categories, so we might even estimate the third bucket and thus the total

I am aware of this question, and believe it confirms my definition but does not answer the question about the actual volume: Bitcoin trade volume and trade transactions


Bonus:
I imagine some of the transactions are simply from one entity to itself. I do not believe this can be identified, but if it is known to represent a certain estimated volume that would be interesting as well.