Pi CPU Temperature

$ RENDER_CHART --type=line --source=sensor-readings.json

SPEC_BREAKDOWN

What this chart teaches

data.url

Loads JSON from a relative path. Vega-Lite fetches it at render time - no bundling needed.

mark: "line" + point layer

The primary mark draws a continuous line. A second layer adds dots at each data point.

encoding.x - temporal

Field type temporal tells Vega-Lite the field is a date/time string, enabling time-aware axis formatting.

encoding.y - quantitative

Numeric measurements. scale: {zero: false} stops the y-axis from forcing a zero baseline.

tooltip

Hover any point. The tooltip array controls which fields appear and how they are formatted.