@turf/length

What is @turf/length?

@turf/length is a module from the Turf.js library that allows you to calculate the length of a GeoJSON LineString or MultiLineString. It is useful for geographic data analysis and manipulation, particularly when working with spatial data in web applications.

What are @turf/length's main functionalities?

Calculate Length of LineString

This feature allows you to calculate the length of a LineString in the specified units (e.g., miles, kilometers). The code sample demonstrates how to create a LineString and calculate its length in miles.

const turf = require('@turf/length');
const line = {
  "type": "Feature",
  "geometry": {
    "type": "LineString",
    "coordinates": [
      [-77.031669, 38.878605],
      [-77.029609, 38.881946],
      [-77.020339, 38.884084],
      [-77.025661, 38.885821]
    ]
  }
};
const length = turf(line, {units: 'miles'});
console.log(length);

Calculate Length of MultiLineString

This feature allows you to calculate the length of a MultiLineString in the specified units (e.g., kilometers). The code sample demonstrates how to create a MultiLineString and calculate its length in kilometers.

const turf = require('@turf/length');
const multiLine = {
  "type": "Feature",
  "geometry": {
    "type": "MultiLineString",
    "coordinates": [
      [
        [-77.031669, 38.878605],
        [-77.029609, 38.881946]
      ],
      [
        [-77.020339, 38.884084],
        [-77.025661, 38.885821]
      ]
    ]
  }
};
const length = turf(multiLine, {units: 'kilometers'});
console.log(length);

Other packages similar to @turf/length

geolib

Geolib is a library for geospatial calculations, including distance and length calculations. It provides similar functionality to @turf/length but also includes additional features like calculating the distance between two points, finding the center of a collection of points, and more. It is more versatile but may be more complex to use for simple length calculations.

geodesy

Geodesy is a library for geodesic calculations, including distance and length calculations. It offers similar functionality to @turf/length but focuses more on precise geodesic calculations, which can be useful for applications requiring high accuracy. It is more specialized and may be overkill for simple length calculations.

README

@turf/length

length

Takes a GeoJSON and measures its length in the specified units, (Multi)Point's distance are ignored.

Parameters

• geojson Feature<(LineString | MultiLineString)> GeoJSON to measure

• options Object Optional parameters (optional, default {})

  • options.units string can be degrees, radians, miles, or kilometers (optional, default kilometers)

Examples

var line = turf.lineString([[115, -32], [131, -22], [143, -25], [150, -34]]);
var length = turf.length(line, {units: 'miles'});

//addToMap
var addToMap = [line];
line.properties.distance = length;

Returns number length of GeoJSON

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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/length

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

$ npm install @turf/turf