Vega / Vega-Lite Visualizer Quick Start: Structure data as array of objects → Choose mark type (bar/line/point/area/arc/rect) → Map encodings (x, y, color, size) to fields → Set data types (quantitative/nominal/ordinal/temporal) → Wrap in
or
```vega
fence. Always include
$schema
, use valid JSON with double quotes, field names are case-sensitive.
Use Vega-Lite for 90% of charts; Vega only for radar, word cloud, force-directed.
Critical Syntax Rules
Rule 1: Always Include Schema
"$schema"
:
"https://vega.github.io/schema/vega-lite/v5.json"
Rule 2: Valid JSON Only
❌ {field: "x",} → Trailing comma, unquoted key
✅ {"field": "x"} → Proper JSON
Rule 3: Field Names Must Match Data
❌ "field": "Category" when data has "category"
✅ "field": "category" → Case-sensitive match
Rule 4: Type Must Be Valid
✅ quantitative | nominal | ordinal | temporal
❌ numeric | string | date
Common Pitfalls
Issue
Solution
Chart not rendering
Check JSON validity, verify
$schema
Data not showing
Field names must match exactly
Wrong chart type
Match mark to data structure
Colors not visible
Check color scale contrast
Dual-axis issues
Add
resolve: {scale: {y: "independent"}}
Output Format
vega-lite
Or for full Vega:
vega {...} ``` Related Files For advanced chart patterns and complex visualizations, refer to references below: examples.md — Stacked bar, grouped bar, multi-series line, area, heatmap, radar (Vega), word cloud (Vega), and interactive chart examples