78 lines
1.9 KiB
Markdown
78 lines
1.9 KiB
Markdown
# @turf/difference
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<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
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## difference
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Finds the difference between two [polygons][1] by clipping the second polygon from the first.
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**Parameters**
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- `polygon1` **[Feature][2]<([Polygon][3] \| [MultiPolygon][4])>** input Polygon feature
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- `polygon2` **[Feature][2]<([Polygon][3] \| [MultiPolygon][4])>** Polygon feature to difference from polygon1
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**Examples**
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```javascript
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var polygon1 = turf.polygon([[
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[128, -26],
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[141, -26],
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[141, -21],
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[128, -21],
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[128, -26]
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]], {
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"fill": "#F00",
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"fill-opacity": 0.1
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});
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var polygon2 = turf.polygon([[
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[126, -28],
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[140, -28],
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[140, -20],
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[126, -20],
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[126, -28]
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]], {
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"fill": "#00F",
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"fill-opacity": 0.1
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});
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var difference = turf.difference(polygon1, polygon2);
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//addToMap
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var addToMap = [polygon1, polygon2, difference];
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```
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Returns **([Feature][2]<([Polygon][3] \| [MultiPolygon][4])> | null)** a Polygon or MultiPolygon feature showing the area of `polygon1` excluding the area of `polygon2` (if empty returns `null`)
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[1]: https://tools.ietf.org/html/rfc7946#section-3.1.6
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[2]: https://tools.ietf.org/html/rfc7946#section-3.2
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[3]: https://tools.ietf.org/html/rfc7946#section-3.1.6
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[4]: https://tools.ietf.org/html/rfc7946#section-3.1.7
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<!-- This file is automatically generated. Please don't edit it directly:
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if you find an error, edit the source file (likely index.js), and re-run
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./scripts/generate-readmes in the turf project. -->
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---
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This module is part of the [Turfjs project](http://turfjs.org/), an open source
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module collection dedicated to geographic algorithms. It is maintained in the
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[Turfjs/turf](https://github.com/Turfjs/turf) repository, where you can create
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PRs and issues.
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### Installation
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Install this module individually:
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```sh
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$ npm install @turf/difference
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```
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Or install the Turf module that includes it as a function:
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```sh
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$ npm install @turf/turf
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```
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