[pcabc]

I wonder how that compares to the cumulative advancing / declining volume line?  But you are comparing the overall market volume with its average.  I'm wondering if there is an indicator here, % stocks trading above their 200 day SMA volume perhaps?  But that does not take account of direction.  So perhaps the indicator would just be comparing the advancing / declining cumulative volume line against its MA?

I imagine it’s similar to what you see in a cumulative line, but it’s nice to be able to see the individual stocks volume intraday in one place to compare how they are acting compared with the last 50 days volume.

Yes.  When I perform my scans I can manually set a breakout level.  This puts a stock on my watchlist and then I can, intraday, fetch the live data and compare the latest price against the breakout level and highlight any that are above it today, especially if they were below it yesterday.  I could envisage comparing the volume against its average as well.

Provided it did not hit my data allowance I can imagine running an intraday scan, running though a set of stocks, filter only the ones above a rising 150 day SMA, and looking for stocks that have broken out above yesterday's channel (Keltner, Doncian whatever) and then extrapolating their volume and comparing that to the average.  That would give a nice intraday screener.   How useful I'm unsure, as I note that a lot of breakouts occur on the open, most of the move can be very  rapid.