@turf/dissolve is a module in the Turf.js library that allows you to merge adjacent or overlapping polygons into a single polygon. This is particularly useful in geographic information systems (GIS) for simplifying complex polygonal data.

What are @turf/dissolve's main functionalities?

Dissolve Polygons

This feature allows you to merge multiple polygons into a single polygon. The code sample demonstrates how to create a collection of polygons and then dissolve them into one polygon using the @turf/dissolve module.

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

const polygons = turf.featureCollection([
  turf.polygon([[
    [-70.603637, -33.399918],
    [-70.614624, -33.395332],
    [-70.639343, -33.392466],
    [-70.659942, -33.394759],
    [-70.683975, -33.404504],
    [-70.697021, -33.419406],
    [-70.701141, -33.434306],
    [-70.700454, -33.446339],
    [-70.694274, -33.458369],
    [-70.682601, -33.465816],
    [-70.668869, -33.472117],
    [-70.646209, -33.473835],
    [-70.624923, -33.472117],
    [-70.609817, -33.468107],
    [-70.595397, -33.458369],
    [-70.587158, -33.442901],
    [-70.587158, -33.426283],
    [-70.590591, -33.414248],
    [-70.594711, -33.406224],
    [-70.603637, -33.399918]
  ]]),
  turf.polygon([[
    [-70.604705, -33.396344],
    [-70.629425, -33.392466],
    [-70.641098, -33.396344],
    [-70.652771, -33.401084],
    [-70.661697, -33.410803],
    [-70.666504, -33.421617],
    [-70.666504, -33.432428],
    [-70.661697, -33.443237],
    [-70.652771, -33.453045],
    [-70.641098, -33.457784],
    [-70.629425, -33.457784],
    [-70.617752, -33.453045],
    [-70.607452, -33.443237],
    [-70.604705, -33.432428],
    [-70.604705, -33.421617],
    [-70.604705, -33.410803],
    [-70.604705, -33.396344]
  ]])
]);

const dissolved = turf.dissolve(polygons);
console.log(JSON.stringify(dissolved));

Other packages similar to @turf/dissolve

@turf/dissolve

dissolve

Dissolves a FeatureCollection of polygons based on a property. Note that multipart features within the collection are not supported

Parameters

featureCollection FeatureCollection<Polygon> input feature collection to be dissolved
propertyName [string] property name on which to dissolve features

Examples

var features = turf.featureCollection([
  turf.polygon([[[0, 0], [0, 1], [1, 1], [1, 0], [0, 0]]], {"combine": "yes"}),
  turf.polygon([[[0, -1], [0, 0], [1, 0], [1, -1], [0,-1]]], {"combine": "yes"}),
  turf.polygon([[[1,-1],[1, 0], [2, 0], [2, -1], [1, -1]]], {"combine": "no"}),
]);

var dissolved = turf.dissolve(features, 'combine');

//addToMap
var addToMap = [features, dissolved]

Returns FeatureCollection<Polygon> a FeatureCollection containing the dissolved polygons

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/dissolve

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

$ npm install @turf/turf

4.6.0 🚀 New Modules

@turf/clean-coords Removes redundant coordinates from any GeoJSON Geometry. (PR https://github.com/Turfjs/turf/pull/875 - Author @stebogit)
@turf/interpolate Takes a set of points and estimates their 'property' values on a grid using the Inverse Distance Weighting (IDW) method.. (PR https://github.com/Turfjs/turf/pull/832 - Author @stebogit)
@turf/clusters-dbscan Takes a set of Points and partition them into clusters according to DBSCAN's data clustering algorithm. (PR https://github.com/Turfjs/turf/pull/812 and https://github.com/Turfjs/turf/pull/851 - Author @DenisCarriere)

special mention to this incredibly instructive and fun interactive map by @DenisCarriere 😎👏
@turf/clusters Provides getCluster, clusterEach, and clusterReduce functions. (PR https://github.com/Turfjs/turf/pull/847 - Author @DenisCarriere)
@turf/boolean-point-on-line Returns true if a point is on a line. Accepts a optional parameter to ignore the start and end vertices of the linestring. (PR https://github.com/Turfjs/turf/pull/858 - Author @rowanwins)
@turf/boolean-overlap Takes two features and returns true or false whether or not they overlap, i.e. whether any pair of edges on the two polygons intersect. If there are any edge intersections, the polygons overlap. (PR https://github.com/Turfjs/turf/pull/856 and https://github.com/Turfjs/turf/pull/868 - Author @stebogit @tcql)
@turf/boolean-equal Determine whether two geometries of the same type have identical X,Y coordinate values. (PR https://github.com/Turfjs/turf/pull/869 - Author @stebogit @tcql)

🏅 New Features/Enhancements

Sets centered param default to true in @turf/point-grid (PR https://github.com/Turfjs/turf/pull/836 - Contributor @stebogit)
Adds MultiLineString support for @turf/point-on-line (PR https://github.com/Turfjs/turf/pull/838 - Contributor @stebogit)
Renames @turf/clusters => @turf/clusters-kmeans, plus adds deprecated warning message to @turf/clusters@4.5.2 (See Issue https://github.com/Turfjs/turf/issues/845)
Changes output type of @turf/clusters-kmeans (See Issue https://github.com/Turfjs/turf/issues/850 - Contributor @DenisCarriere)
Adds segmentEach and segmentReduce functions to @turf/meta (See Issue https://github.com/Turfjs/turf/issues/850 - Contributor @DenisCarriere)
Adds tests and linting on JSDoc in TurfJS core from turf-www; see Issue https://github.com/Turfjs/turf/issues/859 (PR https://github.com/Turfjs/turf/issues/857 + https://github.com/Turfjs/turf/issues/864 + https://github.com/Turfjs/turf/issues/870 - Contributor @DenisCarriere @stebogit)
Introduces null Geometry support across TurfJS modules (See Issue https://github.com/Turfjs/turf/issues/853) (PR https://github.com/Turfjs/turf/issues/866 - Contributor @DenisCarriere)
Includes feature(Sub)Index in coordEach/coordReduce (@turf/meta) 🎉 (PR https://github.com/Turfjs/turf/issues/872 - Contributor @DenisCarriere)
Adds bbox and id params plus geometry method to @turf/helpers (PR https://github.com/Turfjs/turf/issues/877 - Contributor @DenisCarriere)

🐛 Bug Fixes

Applies @turf/truncate to @turf/line-split splitter input to avoid approximation errors. Fixed #852 (PR https://github.com/Turfjs/turf/pull/855)
Fixes @turf-mask error (See Issue https://github.com/Turfjs/turf/issues/837) (PR https://github.com/Turfjs/turf/pull/865 - Contributor @thiagoxvo)
Fixes create-new-module script error on LICENSE file creation (See Issue https://github.com/Turfjs/turf/issues/861) (commit df6986e)
Fixes @turf/isobands error on commonProperties (See Issue https://github.com/Turfjs/turf/issues/831) (commit 1663f07)

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Package last updated on 02 Aug 2017

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