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Price Projections ​

The price chart is a core feature of affini.ag. It combines real auction data with a multi-step smoothing algorithm and forward-looking projections.

Reading the Chart ​

Each vehicle's detail panel includes an interactive price chart powered by amCharts 5. The chart shows:

  • Historical data points — individual auction results plotted over time
  • Smoothed trend line — the processed price curve (see algorithm below)
  • Projection curve — a forward-looking estimate shown as a dashed line

Smoothing Algorithm ​

Raw auction data is noisy — the same car might sell for very different prices on the same day depending on condition, provenance, and auction dynamics. To produce a meaningful trend line, the data goes through a 4-step pipeline:

1. Same-Day Averaging ​

When multiple sales happen on the same date, they are averaged into a single data point. This prevents individual outliers from dominating the chart.

2. Weekly Grouping ​

Data points are bucketed into 7-day periods. This smooths out day-to-day volatility while preserving the overall trend.

3. Simple Moving Average (SMA) ​

A moving average with a window size of 5 is applied. Each point becomes the average of itself and the 4 preceding points, further reducing noise.

4. Exponential Moving Average (EMA) ​

Finally, an EMA with alpha = 0.4 is applied. This gives more weight to recent data while maintaining a smooth curve. The 0.4 alpha provides a balance between responsiveness and stability.

Projection Curves ​

Beyond the historical data, each vehicle may have a projection curve extending into the future. Projections use a quadratic Bezier curve controlled by:

  • Target date — when the projected price is expected to be reached
  • Target price — the projected value in USD
  • Curve parameter (0–10) — controls the dip intensity before the recovery
    • 0 = flat, linear path to the target
    • 5 = moderate dip before rising to the target
    • 10 = deep dip before sharp recovery

Projections are editorially set based on market analysis and are updated as new auction data comes in.

Important Notes ​

  • Price charts reflect auction results only — private sales are not included
  • Projections are editorial estimates, not financial advice
  • The smoothing pipeline means the trend line may lag sudden market shifts by a few weeks
  • All prices are displayed in USD