Annotations

Annotations add explanation without changing the encoded data. Use a line for a threshold, an area or band for a range, a point or arrow for an observation, and a best-fit annotation for a simple linear trend.

from dataviz import Plot, save

def main() raises:
    var plot = (
        Plot()
        .mark_point()
        .encode(x=[1.0, 2.0, 3.0, 4.0], y=[3.0, 5.0, 4.0, 8.0])
        .annotate_line(6.0, label="Target")
        .annotate_point(4.0, 8.0, label="Peak")
        .labels(title="Results Against Target")
    )
    save(plot, "annotations.svg")

Annotation coordinates use data units and the mark’s scale. Out-of-domain fixed annotations are skipped. Point, arrow, and variable bands require two continuous axes; horizontal reference lines work with more mark types. Annotations in facets and layers use the scale of their own cell or layer.

See the annotation recipes and Plot annotation methods.