# turf-concave

> turf concave module

Latest version **3.0.12** (published 2016-07-05) · ISC license · 0 weekly downloads

> **Deprecated.** This package is deprecated.

## Install

```sh
npm install turf-concave
pnpm add turf-concave
yarn add turf-concave
bun add turf-concave
```

## Health

**Score 10/100 (F)** — status: deprecated.

Negative: deprecated.

## Facts

| | |
|---|---|
| Version | 3.0.12 |
| Published | 2016-07-05 |
| First published | 2014-05-29 |
| Weekly downloads | 0 |
| License | ISC |
| TypeScript types | none |
| Module format | CommonJS |
| Dependencies | 4 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 1 |
| Author | Morgan Herlocker |
| Maintainers | cspanring, cwmma, jseppi, jvrousseau, lyzidiamond, morganherlocker, mourner, tcql, tmcw |
| Keywords | turf, gis, geometry |

## Links

- npm: https://www.npmjs.com/package/turf-concave
- Repository: https://github.com/Turfjs/turf-concave
- Issues: https://github.com/Turfjs/turf-concave/issues
- npm.io page: https://npm.io/package/turf-concave

## Dependencies (4)

- [turf-tin](https://npm.io/package/turf-tin.md) ^3.0.12
- [turf-meta](https://npm.io/package/turf-meta.md) ^3.0.12
- [turf-union](https://npm.io/package/turf-union.md) ^3.0.12
- [turf-distance](https://npm.io/package/turf-distance.md) ^3.0.12

## Recent versions

- 3.0.12 (latest) — 2016-07-05
- 3.0.7-canary.ae89c8b3 (canary) — 2016-06-14
- 3.0.10 — 2016-06-15
- 3.0.7 — 2016-06-13
- 3.0.5-canary.4f73aa1a — 2016-06-03
- 3.0.5 — 2016-05-17
- 3.0.1 — 2016-05-16
- 3.0.0-canary.7879bf6c — 2016-05-16
- 3.0.0-canary.2f5f7167 — 2016-05-16
- 1.1.3 — 2015-02-06
- 1.1.2 — 2015-02-06
- 1.1.1 — 2015-02-06
- 1.0.2 — 2014-12-18
- 1.0.1 — 2014-12-18
- 1.0.0 — 2014-12-10
- … 4 more at https://npm.io/package/turf-concave/versions

## README

# turf-concave

# concave

Takes a set of [points](Point) and returns a concave hull polygon.

Internally, this uses [turf-tin](https://github.com/Turfjs/turf-tin) to generate geometries.

**Parameters**

-   `points` **FeatureCollection<Point>** input points
-   `maxEdge` **[number](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number)** the size of an edge necessary for part of the
    hull to become concave (in miles)
-   `units` **[string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String)** used for maxEdge distance (miles or kilometers)

**Examples**

```javascript
var points = {
  "type": "FeatureCollection",
  "features": [
    {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [-63.601226, 44.642643]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [-63.591442, 44.651436]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [-63.580799, 44.648749]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [-63.573589, 44.641788]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [-63.587665, 44.64533]
      }
    }, {
      "type": "Feature",
      "properties": {},
      "geometry": {
        "type": "Point",
        "coordinates": [-63.595218, 44.64765]
      }
    }
  ]
};

var hull = turf.concave(points, 1, 'miles');

var resultFeatures = points.features.concat(hull);
var result = {
  "type": "FeatureCollection",
  "features": resultFeatures
};

//=result
```

-   Throws **[Error](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error)** if maxEdge parameter is missing
-   Throws **[Error](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error)** if units parameter is missing

Returns **Feature<Polygon>** a concave hull

---

This module is part of the [Turfjs project](http://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.

### Installation

Install this module individually:

```sh
$ npm install turf-concave
```

Or install the Turf module that includes it as a function:

```sh
$ npm install turf
```

---
_Source: https://npm.io/package/turf-concave · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._