TL;DR: The three things intraday traders look at most are really just coordinates on one price axis. CDP levels (five reference prices computed from yesterday's high, low and close) suggest roughly how far the day may stretch. Volume by price shows where today's volume piled up; the heaviest bin is the POC. VWAP (intraday cumulative average price) shows roughly what today's participants paid on average. Read together, they tell you where the last price stands. All of this describes price position and trade distribution — it is not a forecast and not investment advice.
Concepts
Why levels and volume belong on the same chart
Levels answer "where might price meet friction?" Volume answers "how much actually traded there?" Apart, each tells half a story: a level with almost no volume around it is just a computed line, while a price bin that absorbed volume all day is a center of gravity the market found on its own.
Put both on one shared price axis and you can finally ask the useful questions: How far is the last price from the nearest level? Did that level see any volume today? Is today's volume center above or below it?
The five CDP levels
CDP (Contrarian Operation System) uses the prior session's high H, low L and close C:
- CDP (pivot) = (H + L + 2C) ÷ 4 — yesterday's center of gravity; the other four derive from it
- NH (near high) = 2 × CDP − L
- NL (near low) = 2 × CDP − H
- AH (absolute high) = CDP + (H − L)
- AL (absolute low) = CDP − (H − L)
Top to bottom: AH, NH, CDP, NL, AL. By convention the area above the pivot leans toward resistance and below it toward support, while AH and AL project yesterday's full range once more in each direction.
Three caveats: (1) this is a single-day, next-session band — a different time scale from multi-month swing levels; (2) it is computed entirely from yesterday's prices — today's news and volume are not in the formula; (3) the wider yesterday's range, the wider the spacing — after a very narrow day the five levels bunch together and mean less.
Volume by price and the POC
Volume by price (a volume profile) bins the day's volume by price rather than by time. A longer bar means more shares changed hands at that price.
The longest bin is the POC (Point of Control) — today's highest-volume price. It is often read as the day's center of gravity: most of the day's turnover happened there, so the market broadly agreed on that price.
Note the change of axis: a normal volume histogram answers "which minute was busy"; a volume profile answers "which price was busy". Same data, different stacking, different question.
VWAP: today's average cost
VWAP is the volume-weighted average price of the session — each trade (or minute) price times its volume, summed, divided by total volume. Because it is volume-weighted, it is closer to "what participants actually paid" than a simple average of open/high/low/close.
Price above VWAP means buyers at that moment are on average in profit on paper; below means the opposite. VWAP accumulates from the open, so it stabilizes as the day progresses — in the first few minutes it tracks price almost exactly and says little.
Price limits: the ceiling and floor of the axis
Taiwan-listed shares (TWSE/TPEx/Innovation Board) and ETFs have a 10% daily limit: take the prior close, apply ±10%, then round to the tick size. Those two prices are the day's physical bounds, which is why they belong at the very top and bottom of the price axis. Emerging-board stocks have no limit and therefore no such bounds.
Application
Reading the chart: three questions
- Where is the last price? Find which segment of the band the last-price line falls in — above the pivot, or between pivot and near low. That is position.
- Where is the volume center? Find the longest bar (POC). A POC above the last price means most of today's turnover happened higher. That is distribution.
- How far is price from VWAP? Above or below decides how today's buyers are doing on average. That is cost.
Each is independent; together they form one sentence, e.g. "price sits below the pivot near the low, the volume center is slightly higher, and it has slipped under VWAP." That describes position and distribution — it does not predict the next bar.
Three common misreadings
- Treating a level as a guaranteed bounce or rejection. Levels are statistical reference prices; price crosses them all the time.
- Treating the POC as support. It only says the most volume changed hands there — no promise it holds on a revisit.
- Reading VWAP too early. Right after the open the sample is tiny and VWAP hugs price.
Data caveats (important)
CTSstock's intraday tab accumulates roughly one snapshot per 60 seconds, so:
- The profile is an estimate bucketed by price, not tick-by-tick data; price moves inside a minute collapse to one point.
- Without tick-level trade direction, bid-side and ask-side volume cannot be separated, so the bars are a single color rather than a red/green split.
- POC resolution is bounded by the tick size (e.g. NT$0.05 below NT$50), which is exactly how the bins are cut.
- The average line is the intraday cumulative VWAP; after the close the full session is shown.
Knowing the caliber is what tells you which questions the chart can and cannot answer. Finer bid/ask or tick-level detail requires a different data source.
Summary
Levels (CDP), the volume center (POC) and average cost (VWAP) each say one thing, sharing a single price axis; the last price cuts across all three, so its position reads at a glance. They describe today's trading structure, not tomorrow's direction — use them as a coordinate system for watching the tape, not as a signal light. This article is technical and educational reference only, not investment advice.