65 lines
2.5 KiB
Markdown
65 lines
2.5 KiB
Markdown
# @turf/transform-scale
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<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
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## transformScale
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Scale GeoJSON objects from a given point by a scaling factor e.g. factor=2
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would make each object 200% larger.
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If a FeatureCollection is provided, the origin point will be calculated
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based on each individual feature *unless* an exact
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### Parameters
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* `geojson` **([GeoJSON][1] | [GeometryCollection][2])** objects to be scaled
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* `factor` **[number][3]** of scaling, positive values greater than 0. Numbers between 0 and 1 will shrink the geojson, numbers greater than 1 will expand it, a factor of 1 will not change the geojson.
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* `options` **[Object][4]** Optional parameters (optional, default `{}`)
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* `options.origin` **(Corners | [Coord][5])** Point from which the scaling will occur (string options: sw/se/nw/ne/center/centroid) (optional, default `'centroid'`)
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* `options.mutate` **[boolean][6]** allows GeoJSON input to be mutated (significant performance improvement if true) (optional, default `false`)
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### Examples
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```javascript
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const poly = turf.polygon([[[0,29],[3.5,29],[2.5,32],[0,29]]]);
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const scaledPoly = turf.transformScale(poly, 3);
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//addToMap
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const addToMap = [poly, scaledPoly];
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scaledPoly.properties = {stroke: '#F00', 'stroke-width': 4};
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```
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Returns **([GeoJSON][1] | [GeometryCollection][2])** scaled GeoJSON
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[1]: https://tools.ietf.org/html/rfc7946#section-3
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[2]: https://tools.ietf.org/html/rfc7946#section-3.1.8
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[3]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number
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[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
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[5]: https://tools.ietf.org/html/rfc7946#section-3.1.1
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[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
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<!-- This file is automatically generated. Please don't edit it directly. If you find an error, edit the source file of the module in question (likely index.js or index.ts), and re-run "yarn docs" from the root of the turf project. -->
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---
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This module is part of the [Turfjs project](https://turfjs.org/), an open source module collection dedicated to geographic algorithms. It is maintained in the [Turfjs/turf](https://github.com/Turfjs/turf) repository, where you can create PRs and issues.
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### Installation
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Install this single module individually:
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```sh
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$ npm install @turf/transform-scale
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```
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Or install the all-encompassing @turf/turf module that includes all modules as functions:
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```sh
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$ npm install @turf/turf
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```
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