@turf/convex

What is @turf/convex?

@turf/convex is a module in the Turf.js library that allows you to compute the convex hull of a set of points. A convex hull is the smallest convex polygon that can enclose all the points in a given dataset. This is useful in various geospatial analyses, such as determining the boundary of a set of geographical points.

What are @turf/convex's main functionalities?

Compute Convex Hull

This feature allows you to compute the convex hull of a set of points. The code sample demonstrates how to create a collection of points and then compute the convex hull using the @turf/convex module.

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

const points = turf.featureCollection([
  turf.point([10, 10]),
  turf.point([20, 20]),
  turf.point([30, 30]),
  turf.point([40, 40]),
  turf.point([50, 50])
]);

const convexHull = turf.convex(points);
console.log(convexHull);

Other packages similar to @turf/convex

hull.js

hull.js is a JavaScript library for computing the convex hull of a set of 2D points. It is lightweight and easy to use, but it focuses solely on convex hull calculations, whereas @turf/convex is part of the larger Turf.js library, which offers a wide range of geospatial analysis tools.

concaveman

concaveman is a fast 2D concave hull algorithm. While it focuses on concave hulls, it can also be used to compute convex hulls by setting the concavity parameter to 1. It is faster and more flexible for certain use cases compared to @turf/convex, but it is not as feature-rich in terms of geospatial analysis.

README

@turf/convex

convex

Takes a Feature or a FeatureCollection and returns a convex hull Polygon.

Internally this uses the convex-hull module that implements a monotone chain hull.

Parameters

• feature (Feature | FeatureCollection) input Feature or FeatureCollection

Examples

var points = {
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [10.195312, 43.755225]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [10.404052, 43.8424511]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [10.579833, 43.659924]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [10.360107, 43.516688]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [10.14038, 43.588348]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [10.195312, 43.755225]
      }
    }
  ]
};

var hull = turf.convex(points);

//addToMap
var addToMap = [points, hull]

Returns Feature<Polygon> a convex hull

---

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/convex

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

$ npm install @turf/turf

Changelog

4.2.0

New Modules

• @turf/sector
• @turf/linestring-to-polygon

Enhancements

• Add mutate param to @turf/flip
• Add Geometry & GeometryCollection support to @turf/truncate
• @turf/inside performance increase
• Add properties param to @turf/circle
• Added bearingToAngle method to turf-helpers

Bug Fixes

• Fix @turf/buffer points in high latitudes
• lineIntersect returns the same point several times
• @turf/flip incorrect if z-elevation is present

Changes

• Change output types @turf/polygon-to-linestring

Documentation

• Update JSDocs examples
• Include many more AddToMap to modules