Path Ordering Recipe

Three chronological country trajectories through fertility and life expectancy space — One explicit year order controls each country's path topology.

Minimal flow

Runnable: install ggaction and provide the named data array as plain row objects.

import { chart } from "ggaction";

const program = chart()
  .createCanvas()
  .createData({ values: observations })
  .createLineMark()
  .encodeX({ field: "fertility" })
  .encodeY({ field: "life_expect" })
  .encodeColor({ field: "country" })
  .encodePathOrder({ field: "year", order: "ascending" })
  .createGuides();

observations is an array of plain row objects. Source rows may be shuffled; the order field controls vertices independently inside each color/group series.

You must decide

The quantitative order field
Ascending or descending order
A color or group field when rows form multiple paths

The library infers

The current compatible Cartesian line
Stable source order as the tie breaker
No extra scale or guide for the topology-only field

Use removePathOrder() to return to the line’s automatic topology.

Continue

Series Encodings · Line-chart recipe