Nah, I heard traders monitoring CMC itself for sudden changes in volume and I wanted to know how they do that.
As far as CMC is concerned, they would be displaying the average of various global exchanges. Hence, it would take time for the volume to completely change as each exchange prices are never interconnected to each other the exception being some low value pump and dump coins. These coins do have varying percentage of trades, volumes and prices. CMC receives its data from various API which the exchanges offer for price and volume tracking and this is probably how CMC would end up with a volume or the average price of coin.
The volume is calculated on the basis of trading happened over in a particular exchange in the past 24 hours. Once they see a pump in volume in various exchanges, the average would be calculated and updated in
24 Hour Volume Report and summing up the various 24 hours they would end up with
Monthly ReportThis is done pair-pair and coin to coin. So a complex and sophisticated system would be running at the backend of the website.
Some additional info from how volume is being calculated in CMC :
(2) Volume (Market Pair)
The volume for each market pair is calculated by taking the 24h volume reported directly from the exchange in quote units, and converting it to USD using CoinMarketCap’s existing reference prices. Let’s take LTC/BTC market as an example:
Let (E) be the 24h volume of LTC/BTC reported directly from the exchange in quote units.
Let (C) be the last known reference price of BTC from CoinMarketCap in USD.
Let (D) be the derived volume reported on CoinMarketCap for the market.
For this example, let (E) = 100 BTC and let (C) = 10,000 USD / 1 BTC.
D = E * C
D = (100 BTC * 10,000 USD / 1 BTC) = 1,000,000 USD
Therefore, the derived volume for LTC/BTC on this specific market pair is $1,000,000 USD.