@turf/points-within-polygon

What is @turf/points-within-polygon?

@turf/points-within-polygon is a module from the Turf.js library that allows you to determine which points from a set of points fall within a given polygon. This is particularly useful for geospatial analysis, such as finding all locations within a specific area.

What are @turf/points-within-polygon's main functionalities?

Filter Points Within a Polygon

This feature allows you to filter a collection of points to find those that fall within a specified polygon. The code sample demonstrates creating a set of points and a polygon, then using the `pointsWithinPolygon` function to find which points are inside the polygon.

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

const points = turf.featureCollection([
  turf.point([0, 0]),
  turf.point([1, 1]),
  turf.point([2, 2]),
  turf.point([3, 3])
]);

const polygon = turf.polygon([[
  [0, 0], [0, 2], [2, 2], [2, 0], [0, 0]
]]);

const pointsWithin = turf.pointsWithinPolygon(points, polygon);
console.log(pointsWithin);

Other packages similar to @turf/points-within-polygon

leaflet

Leaflet is a popular open-source JavaScript library for mobile-friendly interactive maps. It provides similar functionality for geospatial analysis, including the ability to check if points fall within a polygon. However, Leaflet is more focused on rendering maps and providing interactive features, whereas @turf/points-within-polygon is more focused on geospatial calculations.

geolib

Geolib is a library for geospatial calculations in JavaScript. It offers a variety of functions for distance calculations, bounding boxes, and point-in-polygon checks. While it provides similar functionality to @turf/points-within-polygon, Geolib is a more general-purpose library for geospatial calculations, whereas @turf/points-within-polygon is specifically designed for working with points and polygons.

README

@turf/points-within-polygon

pointsWithinPolygon

Finds Points or MultiPoint coordinate positions that fall within (Multi)Polygon(s).

Parameters

• points (Feature | FeatureCollection<(Point | MultiPoint)>) Point(s) or MultiPoint(s) as input search
• polygons (FeatureCollection | Geometry | Feature<(Polygon | MultiPolygon)>) (Multi)Polygon(s) to check if points are within

Examples

var points = turf.points([
    [-46.6318, -23.5523],
    [-46.6246, -23.5325],
    [-46.6062, -23.5513],
    [-46.663, -23.554],
    [-46.643, -23.557]
]);

var searchWithin = turf.polygon([[
    [-46.653,-23.543],
    [-46.634,-23.5346],
    [-46.613,-23.543],
    [-46.614,-23.559],
    [-46.631,-23.567],
    [-46.653,-23.560],
    [-46.653,-23.543]
]]);

var ptsWithin = turf.pointsWithinPolygon(points, searchWithin);

//addToMap
var addToMap = [points, searchWithin, ptsWithin]
turf.featureEach(ptsWithin, function (currentFeature) {
  currentFeature.properties['marker-size'] = 'large';
  currentFeature.properties['marker-color'] = '#000';
});

Returns FeatureCollection<(Point | MultiPoint)> Point(s) or MultiPoint(s) with positions that land within at least one polygon. The geometry type will match what was passsed in

---

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 single module individually:

$ npm install @turf/points-within-polygon

Or install the all-encompassing @turf/turf module that includes all modules as functions:

$ npm install @turf/turf