WEBVTT

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A value depends on its axis. Compare zero-based and truncated scales for 3.6 and 4.25.

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MATHEMATICS · define the relationship and the meaning of each symbol before calculating.

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v: data value; vmin and vmax: displayed axis limits; H: available plot height. The pair is 3.60 and 4.25; Δv = 0.65 for both scales.

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INPUT · unchanged values · read the axis units and the numerical values.

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Compare zero-based and truncated scales for 3.6 and 4.25.

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The numerical difference stays 0.65. Truncating the axis increases the displayed height difference.

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OUTPUT · displayed height difference · read the axis units and the numerical values.

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The displayed difference grows from 0.130H to 0.325H, a factor of 2.5, while the underlying difference stays 0.65.

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CALCULATION · substitute the defined inputs; keep units through each intermediate step.

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Data difference: 4.25 − 3.60 = 0.65 data units

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Full-axis height difference: 0.65 / (5 − 0) = 0.130 fraction of plot height

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Truncated-axis difference: 0.65 / (5 − 3) = 0.325 fraction of plot height

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Visual amplification: 0.325 / 0.130 = 2.5 dimensionless

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SENSITIVITY · change one declared input · read the axis units and the numerical values.

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Axis 0–5: 0.13 fraction of plot height. Full five-unit span.

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Axis 2–5: 0.216667 fraction of plot height. Three-unit span; values unchanged.

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Axis 3–5: 0.325 fraction of plot height. Two-unit span; values unchanged.

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Check: Round-trip representative values through the coordinate mapping, including axis endpoints. Verify that visible labels, SVG positions and downloadable data agree. In a responsive layout, change pixel dimensions without changing the represented values.

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ONE ROW · A dramatic red patch may describe a changing road—or merely a changing legend.

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PARAMETER MAP · 12261 evaluated cells. The colour limits stay fixed across every row.

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The same fixed colour limits apply to every row. A local bump near 650 m sits within a wider spatial wave and a smaller prescribed time oscillation. Compare locations at equal

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time, then revisit one location through the rows. No causal relationship between time and distress is claimed; this is a test signal for inspecting visual encodings.

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VALUE LANDSCAPE · Height and colour encode Synthetic response (m/km). This is a graph over the two input axes, not automatically a physical pavement shape.

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Synthetic response, not a survey or degradation forecast. Automatic per-row colour scaling would destroy direct colour comparability, even though the underlying values remain unchanged.

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A changed visual difference does not change the numerical difference.