Data Layers

Pro 0.11 exposes gm.dataLayers for named feature collections. The host owns its UI and persistence; Geoman owns editing and rendering for layers it creates.

Kind	Data ownership	Editing
Editable	Geoman feature store and source	Full editing; eligible as active draw target
Display	Lightweight Geoman source	No feature editing
External, via adopt()	Existing host map layers	Never owned, restyled, or removed by Geoman

There is no separate interactive kind.

Create and populate an editable layer

Run this after gm:loaded:

gm.dataLayers.add({
  id: 'parcels',
  name: 'Parcels',
  editable: true,
  geometryTypes: ['polygon'],
  style: {
    polygon: { fillColor: '#2563eb', fillOpacity: 0.3, strokeWidth: 2 },
  },
});
await gm.dataLayers.setData('parcels', featureCollection);
gm.dataLayers.setActive('parcels');

New draws go to the active layer. Features retain their home layer across editing, copy, compound geometry operations, and undo/redo.

Manage layers

Method	Purpose
add(spec), remove(id)	Create or remove an owned layer
get(id), list()	Read resolved layer specs
setData(id, geojson)	Await replacement of a layer's data
setStyle(id, style)	Replace style and reset omitted paint properties
setVisibility(id, visible)	Show or hide
setActive(id), getActive()	Select or read the editable draw target
setEditable(id, editable)	Convert display/editable state
reorder(ids)	First ID is frontmost; unknown/external layers are skipped
setSchema(id, schema), validate(id, properties)	Configure/check attributes

get() and list() return shallow spec copies; nested metadata remains host-owned. Keep application state changes explicit through the API.

Attribute-driven styles

gm.dataLayers.setStyle('parcels', {
  polygon: {
    fillColor: {
      categorical: {
        field: 'status',
        categories: { available: '#22c55e', reserved: '#f59e0b' },
        fallback: '#94a3b8',
      },
    },
    fillOpacity: 0.4,
  },
  label: { field: 'name', size: 12, color: '#111827' },
});

Labels require glyphs in the map style. The portable DSL supports get, categorical, step, and interpolate; numeric stops are sorted. Raw MapLibre/Mapbox expression arrays are accepted but make that style renderer-specific. Schema labels/descriptions/option colours are presentation metadata for your application; Geoman does not generate an attribute editor or automatically turn schema option colours into paint.

Integrity and history

geometryTypes restricts accepted geometry. Enable settings.validateSchema for schema enforcement and settings.validateGeometry for geometry checks. Bulk setData() and display-to-editable conversion validate before mutation. History replay restores prior data even if constraints have since changed.

Removing a layer also removes its features parked in editing scratch sources. Disabling the active layer's editability clears that active target.