you may have to look at the exchanges separately and do some math....i'm using crypto-trade, and often the volume numbers there don't line up with the price jumps, so there's an average price adjustment that reflects all of the exchanges, but i think, at least on crypto-trade, the volume graph is for local trades on that particular exchange. i suppose if you signed up on all the exchanges, you could use their api functions to feed you volume data and price data, and merge it to get a clearer picture.... even pricing data seems to vary depending on the exchange. for instance on my multibit wallet for btc, i have mt gox and e-trade prices listed for btc, and they're often different by $100.00 or more. obviously mt gox does a higher volume, so it's prices will have a wider trading range.... which gives me an idea for a follow-up to my article on day trading......