74 lines
2.4 KiB
Markdown
74 lines
2.4 KiB
Markdown
# @turf/collect
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<!-- Generated by documentation.js. Update this documentation by updating the source code. -->
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## collect
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Merges a specified property from a FeatureCollection of points into a
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FeatureCollection of polygons. Given an `inProperty` on points and an `outProperty`
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for polygons, this finds every point that lies within each polygon, collects the
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`inProperty` values from those points, and adds them as an array to `outProperty`
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on the polygon.
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**Parameters**
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- `polygons` **[FeatureCollection][1]<[Polygon][2]>** polygons with values on which to aggregate
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- `points` **[FeatureCollection][1]<[Point][3]>** points to be aggregated
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- `inProperty` **[string][4]** property to be nested from
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- `outProperty` **[string][4]** property to be nested into
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**Examples**
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```javascript
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var poly1 = turf.polygon([[[0,0],[10,0],[10,10],[0,10],[0,0]]]);
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var poly2 = turf.polygon([[[10,0],[20,10],[20,20],[20,0],[10,0]]]);
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var polyFC = turf.featureCollection([poly1, poly2]);
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var pt1 = turf.point([5,5], {population: 200});
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var pt2 = turf.point([1,3], {population: 600});
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var pt3 = turf.point([14,2], {population: 100});
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var pt4 = turf.point([13,1], {population: 200});
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var pt5 = turf.point([19,7], {population: 300});
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var pointFC = turf.featureCollection([pt1, pt2, pt3, pt4, pt5]);
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var collected = turf.collect(polyFC, pointFC, 'population', 'values');
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var values = collected.features[0].properties.values
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//=values => [200, 600]
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//addToMap
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var addToMap = [pointFC, collected]
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```
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Returns **[FeatureCollection][1]<[Polygon][2]>** polygons with properties listed based on `outField`
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[1]: https://tools.ietf.org/html/rfc7946#section-3.3
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[2]: https://tools.ietf.org/html/rfc7946#section-3.1.6
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[3]: https://tools.ietf.org/html/rfc7946#section-3.1.2
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[4]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String
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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/collect
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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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