turf-union

turf-union

union

Takes two polygons and returns a combined polygon. If the input polygons are not contiguous, this function returns a MultiPolygon feature.

Parameters

• poly1 Feature<Polygon> input polygon
• poly2 Feature<Polygon> another input polygon

Examples

var poly1 = {
  "type": "Feature",
  "properties": {
    "fill": "#0f0"
  },
  "geometry": {
    "type": "Polygon",
    "coordinates": [[
      [-82.574787, 35.594087],
      [-82.574787, 35.615581],
      [-82.545261, 35.615581],
      [-82.545261, 35.594087],
      [-82.574787, 35.594087]
    ]]
  }
};
var poly2 = {
  "type": "Feature",
  "properties": {
    "fill": "#00f"
  },
  "geometry": {
    "type": "Polygon",
    "coordinates": [[
      [-82.560024, 35.585153],
      [-82.560024, 35.602602],
      [-82.52964, 35.602602],
      [-82.52964, 35.585153],
      [-82.560024, 35.585153]
    ]]
  }
};
var polygons = {
  "type": "FeatureCollection",
  "features": [poly1, poly2]
};

var union = turf.union(poly1, poly2);

//=polygons

//=union

Returns Feature<(Polygon | MultiPolygon)> a combined Polygon or MultiPolygon feature

---

This module is part of the Turfjs project, an open source module collection dedicated to geographic algorithms. It is maintained in the Turfjs/turf repository, where you can create PRs and issues.

Installation

Install this module individually:

$ npm install turf-union

Or install the Turf module that includes it as a function:

$ npm install turf