DEFRA · dannyleech · Apr 29, 2026 · Apr 29, 2026
diff --git a/demo/js/index.js b/demo/js/index.js
@@ -62,8 +62,7 @@ const interactPlugin = createInteractPlugin({
 	}],
 	debug: true,
 	interactionModes: ['selectMarker', 'placeMarker', 'selectFeature'], // e.g. ['selectMarker'], ['selectFeature'], ['placeMarker'], or combinations
-	// multiSelect: true,
-	contiguous: true,
+	multiSelect: true,
 	deselectOnClickOutside: true
 })
 

diff --git a/docs/plugins/interact.md b/docs/plugins/interact.md
@@ -109,14 +109,6 @@ When `true`, clicking additional features adds them to the selection rather than
 
 ---
 
-### `contiguous`
-**Type:** `boolean`
-**Default:** `false`
-
-When `true`, only features that touch or overlap the existing selection can be added. Uses spatial intersection to determine contiguity. Works with polygons, lines, and points.
-
----
-
 ### `deselectOnClickOutside`
 **Type:** `boolean`
 **Default:** `false`
@@ -350,8 +342,7 @@ Emitted whenever the selected features or selected markers change.
   ],
   selectedMarkers: ['...'],  // array of selected marker IDs
   selectionBounds: [west, south, east, north] | null,
-  canMerge: boolean,  // true when all selected features are contiguous
-  canSplit: boolean   // true when exactly one Polygon or MultiPolygon is selected
+  contiguous: boolean  // true when 2+ features are selected and all form a single contiguous group
 }
 ```
 

diff --git a/plugins/interact/src/defaults.js b/plugins/interact/src/defaults.js
@@ -2,7 +2,6 @@ export const DEFAULTS = {
   tolerance: 10,
   interactionModes: ['selectMarker'],
   multiSelect: false,
-  contiguous: false,
   deselectOnClickOutside: false,
   marker: {},
   selectedStrokeWidth: 3

diff --git a/plugins/interact/src/hooks/useInteractionHandlers.js b/plugins/interact/src/hooks/useInteractionHandlers.js
@@ -1,5 +1,5 @@
 import { useCallback, useEffect, useRef } from 'react'
-import { isContiguousWithAny, canSplitFeatures, areAllContiguous } from '../utils/spatial.js'
+import { areAllContiguous } from '../utils/spatial.js'
 import { getFeaturesAtPoint, findMatchingFeature, buildLayerConfigMap } from '../utils/featureQueries.js'
 import { scaleFactor } from '../../../../src/config/appConfig.js'
 import { isStandaloneLabel } from '../../../../src/utils/symbolUtils.js'
@@ -59,8 +59,7 @@ const useSelectionChangeEmitter = (eventBus, selectedFeatures, selectedMarkers,
       selectedFeatures,
       selectedMarkers,
       selectionBounds,
-      canMerge: areAllContiguous(selectedFeatures),
-      canSplit: canSplitFeatures(selectedFeatures)
+      contiguous: areAllContiguous(selectedFeatures)
     })
 
     lastEmittedSelectionChange.current = { features: selectedFeatures, markers: selectedMarkers }
@@ -84,13 +83,12 @@ const useSelectionChangeEmitter = (eventBus, selectedFeatures, selectedMarkers,
  */
 export const useInteractionHandlers = ({ mapState, pluginState, services, mapProvider }) => {
   const { markers, mapSize } = mapState
-  const { dispatch, layers, interactionModes, multiSelect, contiguous, marker: markerOptions, tolerance, selectedFeatures, selectedMarkers, selectionBounds, deselectOnClickOutside } = pluginState
+  const { dispatch, layers, interactionModes, multiSelect, marker: markerOptions, tolerance, selectedFeatures, selectedMarkers, selectionBounds, deselectOnClickOutside } = pluginState
   const { eventBus } = services
   const layerConfigMap = buildLayerConfigMap(layers)
   const scale = scaleFactor[mapSize] ?? 1
   const processFeatureMatch = useCallback(({ feature, config }) => {
     markers.remove('location')
-    const isNewContiguous = contiguous && isContiguousWithAny(feature, selectedFeatures)
     const featureId = feature.properties?.[config.idProperty] ?? feature.id
     if (featureId == null) {
       return
@@ -103,11 +101,10 @@ export const useInteractionHandlers = ({ mapState, pluginState, services, mapPro
         layerId: config.layerId,
         idProperty: config.idProperty,
         properties: feature.properties,
-        geometry: feature.geometry,
-        replaceAll: contiguous && !isNewContiguous
+        geometry: feature.geometry
       }
     })
-  }, [markers, contiguous, selectedFeatures, dispatch, multiSelect])
+  }, [markers, dispatch, multiSelect])
 
   const processFallback = useCallback(({ coords }) => {
     const canPlace = interactionModes.includes('placeMarker')

diff --git a/plugins/interact/src/hooks/useInteractionHandlers.test.js b/plugins/interact/src/hooks/useInteractionHandlers.test.js
@@ -1,15 +1,11 @@
 import { renderHook, act } from '@testing-library/react'
 import { useInteractionHandlers } from './useInteractionHandlers.js'
 import * as featureQueries from '../utils/featureQueries.js'
-import { isContiguousWithAny } from '../utils/spatial.js'
-
 /* ------------------------------------------------------------------ */
 /* Mocks                                                              */
 /* ------------------------------------------------------------------ */
 
 jest.mock('../utils/spatial.js', () => ({
-  isContiguousWithAny: jest.fn(),
-  canSplitFeatures: jest.fn(() => false),
   areAllContiguous: jest.fn(() => false)
 }))
 jest.mock('../utils/featureQueries.js', () => ({
@@ -48,7 +44,6 @@ const setup = (pluginOverrides = {}, markerItems = [], markerRefs = new Map()) =
       layers: [{ layerId: 'parcels', idProperty: 'parcelId' }],
       interactionModes: ['selectMarker', 'selectFeature'],
       multiSelect: false,
-      contiguous: false,
       marker: { symbol: 'pin', backgroundColor: 'red' },
       selectedFeatures: [],
       selectedMarkers: [],
@@ -257,58 +252,6 @@ it('passes multiSelect flag through to dispatch', () => {
   )
 })
 
-/* ------------------------------------------------------------------ */
-/* Contiguous selection (FULL COVERAGE)                               */
-/* ------------------------------------------------------------------ */
-
-describe('contiguous selection', () => {
-  it('does NOT replace selection when feature is contiguous', () => {
-    isContiguousWithAny.mockReturnValue(true) // contiguous
-
-    const { result, deps } = setup({
-      contiguous: true,
-      selectedFeatures: [{ geometry: { type: 'Polygon' } }]
-    })
-
-    click(result)
-
-    expect(deps.pluginState.dispatch).toHaveBeenCalledWith(
-      expect.objectContaining({
-        payload: expect.objectContaining({
-          replaceAll: false
-        })
-      })
-    )
-  })
-
-  it('replaces selection when feature is NOT contiguous', () => {
-    isContiguousWithAny.mockReturnValue(false) // disjoint
-
-    const { result, deps } = setup({
-      contiguous: true,
-      selectedFeatures: [{ geometry: { type: 'Polygon' } }]
-    })
-
-    click(result)
-
-    expect(deps.pluginState.dispatch).toHaveBeenCalledWith(
-      expect.objectContaining({
-        payload: expect.objectContaining({
-          replaceAll: true
-        })
-      })
-    )
-  })
-
-  it('does not compute contiguity when contiguous is false', () => {
-    const { result } = setup({ contiguous: false })
-
-    click(result)
-
-    expect(isContiguousWithAny).not.toHaveBeenCalled()
-  })
-})
-
 /* ------------------------------------------------------------------ */
 /* deselectOnClickOutside                                             */
 /* ------------------------------------------------------------------ */
@@ -384,6 +327,23 @@ it('does not check markers when selectMarker is not in interactionModes', () =>
 /* Selection change event                                             */
 /* ------------------------------------------------------------------ */
 
+it('does not emit selectionchange when features are selected but bounds not yet calculated', () => {
+  const deps = {
+    mapState: { markers: { add: jest.fn(), remove: jest.fn(), items: [], markerRefs: new Map() } },
+    pluginState: {
+      selectedFeatures: [{ featureId: 'F1' }],
+      selectedMarkers: [],
+      selectionBounds: null
+    },
+    services: { eventBus: { emit: jest.fn() } },
+    mapProvider: {}
+  }
+
+  renderHook(() => useInteractionHandlers(deps))
+
+  expect(deps.services.eventBus.emit).not.toHaveBeenCalled()
+})
+
 it('emits selectionchange once when bounds exist', () => {
   const deps = {
     mapState: { markers: { add: jest.fn(), remove: jest.fn(), items: [], markerRefs: new Map() } },
@@ -404,8 +364,7 @@ it('emits selectionchange once when bounds exist', () => {
       selectedFeatures: deps.pluginState.selectedFeatures,
       selectedMarkers: [],
       selectionBounds: deps.pluginState.selectionBounds,
-      canMerge: false,
-      canSplit: false
+      contiguous: false
     })
   )
 })

diff --git a/plugins/interact/src/reducer.js b/plugins/interact/src/reducer.js
@@ -4,7 +4,6 @@ const initialState = {
   marker: null,
   interactionModes: null,
   multiSelect: false,
-  contiguous: false,
   deselectOnClickOutside: false,
   selectedFeatures: [],
   selectedMarkers: [],

diff --git a/plugins/interact/src/reducer.test.js b/plugins/interact/src/reducer.test.js
@@ -8,7 +8,6 @@ describe('initialState', () => {
       marker: null,
       interactionModes: null,
       multiSelect: false,
-      contiguous: false,
       deselectOnClickOutside: false,
       selectedFeatures: [],
       selectedMarkers: [],

diff --git a/plugins/interact/src/utils/spatial.js b/plugins/interact/src/utils/spatial.js
@@ -41,20 +41,6 @@ function isContiguousWithAny (feature, features) {
   return features.some(f => !booleanDisjoint(toTurfGeometry(f), toTurfGeometry(feature)))
 }
 
-/**
- * Check if a single polygon/multipolygon feature can be split.
- *
- * @param {Array} features - Array of features
- * @returns {boolean} True if exactly one polygon or multipolygon feature
- */
-function canSplitFeatures (features) {
-  if (features.length !== 1) {
-    return false
-  }
-  const type = features[0].geometry?.type
-  return type === 'Polygon' || type === 'MultiPolygon'
-}
-
 /**
  * Check if all features form a single contiguous group (can be merged).
  * Uses flood-fill to find connected components.
@@ -94,6 +80,5 @@ function areAllContiguous (features) {
 export {
   toTurfGeometry,
   isContiguousWithAny,
-  canSplitFeatures,
   areAllContiguous
 }
diff --git a/plugins/interact/src/utils/spatial.test.js b/plugins/interact/src/utils/spatial.test.js
@@ -1,4 +1,4 @@
-import { toTurfGeometry, isContiguousWithAny, canSplitFeatures, areAllContiguous } from './spatial.js'
+import { toTurfGeometry, isContiguousWithAny, areAllContiguous } from './spatial.js'
 import { polygon, multiPolygon, lineString, multiLineString, point, multiPoint } from '@turf/helpers'
 
 describe('toTurfGeometry', () => {
@@ -61,18 +61,6 @@ describe('isContiguousWithAny', () => {
   })
 })
 
-describe('canSplitFeatures', () => {
-  it.each([
-    [[{ geometry: { type: 'Polygon' } }], true],
-    [[{ geometry: { type: 'MultiPolygon' } }], true],
-    [[{ geometry: { type: 'LineString' } }], false],
-    [[], false],
-    [[{ geometry: { type: 'Polygon' } }, { geometry: { type: 'Polygon' } }], false]
-  ])('returns expected result for %j', (features, expected) => {
-    expect(canSplitFeatures(features)).toBe(expected)
-  })
-})
-
 describe('areAllContiguous', () => {
   const poly = (coords) => ({ geometry: { type: 'Polygon', coordinates: [coords] } })
   const A = poly([[0, 0], [2, 0], [2, 2], [0, 2], [0, 0]])