@turf/transform-rotate

What is @turf/transform-rotate?

@turf/transform-rotate is a module from the Turf.js library that allows you to rotate geometries by a specified angle around a given pivot point. This can be useful for various geospatial data manipulations, such as aligning features or creating rotated versions of existing geometries.

What are @turf/transform-rotate's main functionalities?

Rotate a Point

This feature allows you to rotate a point geometry by a specified angle. In this example, a point at coordinates [0, 0] is rotated by 45 degrees.

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

const point = turf.point([0, 0]);
const rotatedPoint = turf.transformRotate(point, 45);
console.log(rotatedPoint);

Rotate a Polygon

This feature allows you to rotate a polygon geometry by a specified angle. In this example, a square polygon is rotated by 90 degrees.

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

const polygon = turf.polygon([[
  [0, 0],
  [1, 0],
  [1, 1],
  [0, 1],
  [0, 0]
]]);
const rotatedPolygon = turf.transformRotate(polygon, 90);
console.log(rotatedPolygon);

Rotate around a Custom Pivot

This feature allows you to rotate a geometry around a custom pivot point. In this example, a line is rotated by 45 degrees around the pivot point [1, 1].

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

const line = turf.lineString([[0, 0], [2, 2]]);
const pivot = [1, 1];
const rotatedLine = turf.transformRotate(line, 45, { pivot });
console.log(rotatedLine);

Other packages similar to @turf/transform-rotate

jsts

JSTS (JavaScript Topology Suite) is a library for performing various geometric operations, including transformations like rotation. It offers a more comprehensive set of geometric operations compared to @turf/transform-rotate, but it may be more complex to use for simple tasks.

geolib

Geolib is a library for geospatial calculations and transformations. It provides functions for rotating points and other geometries, similar to @turf/transform-rotate, but it also includes a broader range of geospatial utilities such as distance calculations and bounding box operations.

README

@turf/transform-rotate

transformRotate

Rotates any geojson Feature or Geometry of a specified angle, around its centroid or a given pivot point.

Parameters

• geojson GeoJSON object to be rotated

• angle number of rotation in decimal degrees, positive clockwise

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

  • options.pivot Coord point around which the rotation will be performed (optional, default 'centroid')
  • options.mutate boolean allows GeoJSON input to be mutated (significant performance increase if true) (optional, default false)

Examples

const poly = turf.polygon([[[0,29],[3.5,29],[2.5,32],[0,29]]]);
const options = {pivot: [0, 25]};
const rotatedPoly = turf.transformRotate(poly, 10, options);

//addToMap
const addToMap = [poly, rotatedPoly];
rotatedPoly.properties = {stroke: '#F00', 'stroke-width': 4};

Returns GeoJSON the rotated GeoJSON feature

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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/transform-rotate

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

$ npm install @turf/turf