STACKED AREA

stacked filled bands over time, bottom-up. Needs: ordered periods + 2-4 non-negative component series summing to a meaningful total.

trendcompositionchange-over-time

DL-01 AGRAW

Use when

how a growing total splits into components over time
the total AND its composition are both the story

Do not use when

reading exact middle-band values (baselines wander; CH-TIM-01)
more than 4 components
any negative values

See instead

single quantity: CH-TIM-03
shares matter more than levels: CH-PTW-02
series cross and levels must be read exactly: CH-TIM-01

Alternatives

CH-TIM-03 (one series)
CH-PTW-01 (few periods)

Rules

bands ordered largest at the bottom; only the bottom band has a straight baseline
segments named at their right ends, never a legend
y starts at zero

Never do this

more than 4 bands
legends
reading middle bands as levels
negative components

QA before delivering

<= 4 components, all >= 0
largest band at bottom
names at band ends
unit once
source present

Data shape

title	action title with a number
source	bottom-left always
unit	on the top tick
x	ordered period labels
series	bottom-up components [{name, values}], largest first

Sample data (golden)

{
  "title": "Site work now drives a third of monthly output",
  "eyebrow": "OUTPUT BY STAGE . 2026",
  "source": "Source: sample dataset v1, 2026-07-12",
  "unit": " units",
  "x": [
    "Jan",
    "Feb",
    "Mar",
    "Apr",
    "May",
    "Jun",
    "Jul",
    "Aug"
  ],
  "series": [
    {
      "name": "Fabrication",
      "values": [
        12,
        14,
        16,
        18,
        20,
        22,
        24,
        26
      ]
    },
    {
      "name": "Transport",
      "values": [
        4,
        6,
        8,
        9,
        11,
        12,
        14,
        15
      ]
    },
    {
      "name": "Site",
      "values": [
        2,
        3,
        5,
        7,
        9,
        12,
        15,
        18
      ]
    }
  ]
}