@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 = turf.featureCollection([
  turf.point([19.026432, 47.49134]),
  turf.point([19.074497, 47.509548])
]);

var combined = turf.combine(fc);

//addToMap
var addToMap = [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

6.2.0

After a bit of hiatus, TurfJS is resuming releases.

⭐️ Major Updates

• ES Modules available for all packages
• Tree shaking should significantly reduce import size of @turf/turf
• Better support for ESM modules (PR https://github.com/Turfjs/turf/pull/1942 - Author @diachedelic)
• Clean-up of test and benchmark running to make publishing easier
• Enforce styling using Prettier
• Enable ESLint and get rid of unused variables
• Upgrade rollup for more correct javascript module builds
• Only include ES5 code

🚀 New Modules

[@turf/boolean-touches][boolean-touches]

Determines if two features touch but do not intersect

[@turf/boolean-valid][boolean-valid]

Checks if the geometry is a valid according to the OGC Simple Feature Specification

[@turf/quadrat-analysis][quadrat-analysis]

Performs a quadrat analysis on a set of points

[@turf/rectangle-grid][rectangle-grid]

Creates a grid of rectangles from a bounding box

[@turf/voroni][voronoi]

Typescript types for the options parameter have been fixed (PR https://github.com/Turfjs/turf/pull/1424 - Author @stevage)

[@turf/points-within-polygon][points-within-polygon]

Typescript types around the Feature's Properties will now be preserved. (PR https://github.com/Turfjs/turf/pull/1761 - Author @rugheid)

[@turf/rewind][rewind]

Typescript types for the 'reverse' option are now correct. Previously it was misnamed as 'reversed'. (PR https://github.com/Turfjs/turf/pull/1786 - Author @jonnycornwell)

[@turf/difference][difference]

No longer publishes an .mjs file.

[@turf/meta][meta]

No longer publishes an .mjs file.

[@turf/tag][tag]

Add MultiPolygon support. (PR https://github.com/Turfjs/turf/pull/1996 - Author bryceroney)

🐛 Bug Fixes

• @turf/centroid Don't visit first point twice when calculating centroid (PR https://github.com/Turfjs/turf/pull/1894 - Author @rowanwins)

• @turf/transform-translate Better handling of negative distances (PR https://github.com/Turfjs/turf/pull/1895 - Author @rowanwins)

• @turf/union, @turf/difference, @turf/intersect Use polygon-clipping library to fix correctness issues (PR https://github.com/Turfjs/turf/pull/1916 - Authors @mbullington, @ngottlieb)

• @turf/buffer Change default number of steps to 8, and actually support the steps option (PR https://github.com/Turfjs/turf/pull/1931 - Author stevenchanin)

• @turf/buffer Fix projection issues that produce undersized buffers at non-equatorial latitudes (PR https://github.com/Turfjs/turf/pull/1956 - Author dyakovlev)

• @turf/helpers Add runtime checks to point() method, fixing an API break (PR https://github.com/Turfjs/turf/pull/1964)

🏅 New Features/Enhancements

• @turf/boolean-overlap Better performance for MultiPoint geometries (PR https://github.com/Turfjs/turf/pull/1910 - Author @mfedderly)

• @turf/helpers Add hectares to convertArea (PR https://github.com/Turfjs/turf/pull/1943 - Author @DanielJDufour)

• @turf/great-circle Update Typescript types to support MultiLineString input (PR https://github.com/Turfjs/turf/pull/1928 - Author kronick)

📖 Documentation

• @turf/square-grid Clarify inputs (PR https://github.com/Turfjs/turf/pull/1885 - Author @raphael-leger)

• @turf/greater-circle Clarify properties option example (PR https://github.com/Turfjs/turf/pull/1888 - Author @chris-catignani)

⚠️ Breaking Change

• @turf/line-to-polygon no longer modifies its input unless the mutate option is true (PR https://github.com/Turfjs/turf/pull/1879 - Author @MortenBirk)

• @turf/unkink-polygon remove Number.prototype.modulo override (PR https://github.com/Turfjs/turf/pull/1978)