union

Description

Takes a collection of input polygons and returns a combined polygon. If the input polygons are not contiguous, this function returns a multi-polygon feature.

Parameters

Name	Type	Description
features	FeatureCollection<Polygon | MultiPolygon>	input polygon features
options?	Object	Optional Parameters (default {})
options.properties?	GeoJsonProperties	properties to assign to output feature (default {})

Returns

Feature<Polygon | MultiPolygon> | null a combined polygon or multi-polygon feature, or null if there were no input polygons to combine

Examples

const poly1 = turf.polygon(
  [
    [
      [-82.574787, 35.594087],
      [-82.574787, 35.615581],
      [-82.545261, 35.615581],
      [-82.545261, 35.594087],
      [-82.574787, 35.594087],
    ],
  ],
  { fill: "#0f0" },
);

const poly2 = turf.polygon([
  [
    [-82.560024, 35.585153],
    [-82.560024, 35.602602],
    [-82.52964, 35.602602],
    [-82.52964, 35.585153],
    [-82.560024, 35.585153],
  ],
]);

const union = turf.union(turf.featureCollection([poly1, poly2]));

Installation

$ npm install @turf/union

import { union } from "@turf/union";
const result = union(...);

$ npm install @turf/turf

import * as turf from "@turf/turf";
const result = turf.union(...);