Vortex Indicator

The Vortex Indicator (VI), developed by Etienne Botes and Douglas Siepman, identifies the start of new trends and their direction. It uses two lines — VI+ (positive) and VI- (negative) — derived from the relationship between current and previous highs and lows, normalized by the Average True Range.

VM+ = |High - Low_prev|
VM- = |Low - High_prev|
TR  = max(High - Low, |High - Close_prev|, |Low - Close_prev|)

VI+ = Sum(VM+, N) / Sum(TR, N)
VI- = Sum(VM-, N) / Sum(TR, N)

• Two oscillating lines — VI+ and VI- typically range from 0.5 to 1.5.
• Trend identification — the dominant line indicates trend direction.
• ATR-normalized — adapts to volatility across different instruments and timeframes.

Bullish

• VI+ crosses above VI- — uptrend beginning.
• VI+ above VI- — uptrend in progress.

Bearish

• VI- crosses above VI+ — downtrend beginning.
• VI- above VI+ — downtrend in progress.

Strong trend

• Wide separation between VI+ and VI- — strong trend momentum.

| Parameter | Default | Description | |-----------|---------|-------------| | Period | 14 | Lookback window |

| Component | Description | |-----------|-------------| | VORTEX_VI_PLUS(14) | Positive vortex line | | VORTEX_VI_MINUS(14) | Negative vortex line |

| Condition | Meaning | |-----------|---------| | VORTEX_VI_PLUS(14) > VORTEX_VI_MINUS(14) | Uptrend in progress | | VORTEX_VI_PLUS(14) cross_over VORTEX_VI_MINUS(14) | Bullish crossover — new uptrend | | VORTEX_VI_MINUS(14) cross_over VORTEX_VI_PLUS(14) | Bearish crossover — new downtrend | | VORTEX_VI_PLUS(14) > 1.1 | Strong bullish momentum |

• Vortex is one of the best indicators for catching trend reversals early.
• Combine with ADX or a moving average to filter weak signals.
• Period 14 is standard; shorter periods (7-10) for scalping, longer (21-30) for position trading.
• Watch for VI+ and VI- converging — this often precedes a breakout in either direction.