Chart widget

Render a bar, line, or pie chart bound to a layer or derived layer. Updates live as the map filters.

intermediate

The Chart widget renders a chart inside a Custom Web App, bound to a layer or derived layer's data. Use to surface a small data viz alongside the map: incident counts per month, a status distribution, an average over time.

What it can render

  • Bar chart (vertical or horizontal). Discrete categories along one axis, a numeric metric along the other.
  • Pie / donut chart. Share of total per category. Best for small category counts.
  • Line chart. A metric over an ordered axis (typically time).
  • Number indicator (single big number with optional trend). Use for a one-off "X total" readout, not a comparison.

Inputs

  • Bound layer. A data layer, derived layer, or ArcGIS service.
  • Category field (bar / pie / line). The discrete groups. For line charts, the x-axis field (a date or ordered numeric).
  • Value field (bar / line). The numeric metric per category.
  • Aggregation: count(*), sum, avg, min, max.
  • Sort: by category (alphabetical), by value (descending or ascending), or custom.
  • Limit: top N categories shown; the rest grouped as "Other" (optional).

Live filtering

The chart re-queries on map filter change. Filtering the bound layer (via layer-list, filter widget, or a category click on this same chart) updates the data. This is the cross-widget filter pattern: clicking a bar can drill into "only that category" elsewhere.

Widget config

  • Chart type: bar / pie / line / number.
  • Bound layer and fields (as above).
  • Title (optional).
  • Color palette: built-in palettes, or define per-category colors that match the layer's symbology (the "match symbology" toggle).
  • Refresh interval (default: on map filter change; can also poll every N seconds).

Notes

  • Big aggregates are slow. A bar chart binning a million features per category over an unindexed field can take seconds. Build a pre-aggregated derived layer for hot dashboards.
  • For a screen-filling dashboard, use the Dashboard item type, not a Custom Web App with a chart widget. Charts in apps are best as one-or-two-widget accents alongside a map.