@turf/combine

What is @turf/combine?

@turf/combine is a module from the Turf.js library that allows you to combine multiple GeoJSON features into a single feature collection. This is particularly useful for merging multiple geometries into a single collection for easier manipulation and analysis.

What are @turf/combine's main functionalities?

Combine Multiple Features

This feature allows you to combine multiple GeoJSON features (points, lines, polygons) into a single feature collection. The code sample demonstrates combining two points and a line into one feature collection.

const turf = require('@turf/turf');

const point1 = turf.point([0, 0]);
const point2 = turf.point([2, 2]);
const line = turf.lineString([[1, 1], [3, 3]]);

const combined = turf.combine(turf.featureCollection([point1, point2, line]));

console.log(JSON.stringify(combined));

Other packages similar to @turf/combine

geojson-merge

The geojson-merge package allows you to merge multiple GeoJSON files into one. It is similar to @turf/combine in that it combines multiple GeoJSON features, but it is more focused on merging files rather than individual features.

geojson-flatten

The geojson-flatten package is used to flatten nested GeoJSON geometries into a single-level feature collection. While @turf/combine focuses on combining features, geojson-flatten is useful for simplifying complex nested structures.

geojson-utils

The geojson-utils package provides a variety of utility functions for working with GeoJSON data, including combining features. It offers a broader range of functionalities compared to @turf/combine, which is specialized for combining features.

README

@turf/combine

combine

Combines a FeatureCollection of Point, LineString, or Polygon features into MultiPoint, MultiLineString, or MultiPolygon features.

Parameters

• fc FeatureCollection<(Point | LineString | Polygon)> a FeatureCollection of any type

Examples

var fc = {
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [19.026432, 47.49134]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [19.074497, 47.509548]
      }
    }
  ]
};

var combined = turf.combine(fc);

//=combined

Returns FeatureCollection<(MultiPoint | MultiLineString | MultiPolygon)> a FeatureCollection of corresponding type to input

---

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/combine

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

$ npm install @turf/turf

Changelog

4.1.0

New Modules

• @turf/line-arc
• @turf/polygon-to-linestring
• @turf/bbox-clip
• @turf/line-overlap

Enhancements

• added centered param to point-grid (PR: https://github.com/Turfjs/turf/pull/650)
• Single module.export helpers, invariant & meta (Commit: https://github.com/Turfjs/turf/commit/9cebb2100cf545fec49488c80140909ab54358b5)

Bug Fixes

• Turf.invariant fails on string value as coordinate (PR: https://github.com/Turfjs/turf/pull/643)
• Handle precision=0 turf-truncate (PR: https://github.com/Turfjs/turf/pull/641)
• Added radiansToDistance, distanceToRadians & distanceToDegrees to Turf core library from @turf/helpers. (Commit: https://github.com/Turfjs/turf/commit/a88d77a3e7f76860b3c138a716da8b603a407c8e)
• Removed process.hrtime in @turf/polygon-unkink(issue: https://github.com/mclaeysb/simplepolygon/issues/5)