Data analyzer

What it does

Data analyzer examines the attributes in a vector layer and suggests useful ways to understand or map them. It identifies numeric fields, missing and no-data values, likely identifiers, correlations, statistical families, and likely borders between groups of related attributes.

The family detector uses field names in several languages, including Dutch, English, Spanish, Finnish, and Greek. It also looks at the values themselves: percentages that form a whole, complementary fields, additive totals, and strongly related measures can reveal a family even when the field names are short, abbreviated, or unfamiliar.

The analysis runs in a Web Worker. The map remains usable while a large layer is being processed, and the panel reports that it is calculating. Canceling terminates the current calculation; refresh starts a new one.

Using it

1. Open Data analyzer and choose a vector layer.
2. Wait for the complete analysis to finish. The panel reports the feature count and offers tabs for map options, fields, and families.
3. Review a suggested profile, percentage, or relationship.
4. Press Map this to apply a suitable graduated style to the selected field.

The analyzer uses all features available to the browser. GeoJSON, converted dropped data, and a complete WFS response can therefore be analyzed as a whole. For MVT or other tiled sources, the browser normally has only the currently loaded tile features. The tool warns about this: its result describes the loaded view, not necessarily the complete dataset. Pan or zoom and refresh to analyze another loaded extent.

No preview or sampling result is presented. A calculation is either still running, complete, or canceled.

In your own map

Add data-analyzer to a toolbar. It needs no extra tool settings:

{
  "tools": {
    "data-analyzer": {
      "type": "data-analyzer",
      "enabled": true
    },
    "mainToolbar": {
      "type": "toolbar",
      "enabled": true,
      "position": "top-left",
      "orientation": "vertical",
      "items": [
        {
          "type": "data-analyzer",
          "id": "data-analyzer",
          "enabled": true
        }
      ]
    }
  }
}

The analyzer reads data through the active map adapter. Geometry is kept on the main thread and only feature properties are sent to the worker, which avoids copying large polygon geometries while preserving the full attribute analysis.

Extending it

The pure analysis logic lives in src/utils/data-analyzer.ts, so it can be tested without a browser or map engine. The component collects available features, sends their properties to src/workers/data-analyzer.worker.ts, and renders the returned DatasetAnalysis.

Keep the distinction between complete and tile-backed data visible when adding new suggestions. A useful future extension is a full-data endpoint for tiled layers, allowing the worker to analyze the complete source rather than the features currently loaded in the viewport.

Map this currently turns a single-field suggestion into a style-builder classification and applies it through the adapter. Future map actions can use the detected family to create coordinated multi-field maps, small multiples, or derived profile layers while keeping the analyzer independent from styling implementation details.