Line Chart Templates

Line chart templates are built for one job: showing how a number moves over time, continuously, not just at a handful of checkpoints. Where a bar chart treats each period as a separate box to compare, a line chart draws the path between them, so the shape of the change (a steady climb, a sharp spike, a slow bleed) is the whole point. The four templates in this category share that time-axis foundation but disagree on what else they encode: individual series, cumulative volume, overlapping categories, or shifting rank.

The line-versus-area choice is the one decision worth getting right before you pick a template. A line chart plots values with nothing underneath, good for comparing several series at once since your eye reads relative height without extra ink in the way. An area chart fills the space below the line, and that fill isn't decorative. It visually implies volume or accumulation, so it reads as an amount even when your data is really just a rate. Stack several areas and you gain a sense of the total, but you lose the ability to read any single series cleanly; only the bottom layer sits on a flat baseline.

Stream graph and bump chart are the specialised cases. A stream graph is a stacked area chart with no fixed baseline. It flows symmetrically around a center line instead, trading precise reading for a shape that's easier to scan across many overlapping categories, like genre popularity across decades of music sales. A bump chart drops values entirely and plots rank instead, which is the right call when the story is who's in first place and when that changed, not how big the gap between them was.