https://github.com/rowanwins/convex-hull-wp

A convex hull implementation based on the paper by Wijeweera & Pinidiyaarachchi
https://github.com/rowanwins/convex-hull-wp

computational-geometry convex-hull convex-hull-algorithms convexhull

Last synced: 28 days ago
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A convex hull implementation based on the paper by Wijeweera & Pinidiyaarachchi

• Host: GitHub
• URL: https://github.com/rowanwins/convex-hull-wp
• Owner: rowanwins
• License: mit
• Created: 2019-07-13T12:53:52.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2022-07-19T06:22:50.000Z (over 2 years ago)
• Last Synced: 2024-05-27T19:11:04.121Z (5 months ago)
• Topics: computational-geometry, convex-hull, convex-hull-algorithms, convexhull
• Language: JavaScript
• Size: 595 KB
• Stars: 2
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGES.md
  • License: LICENSE

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README

        
# convex-hull-wp

A small and fast module for generating convex hulls from a set of points based on the algorithm by Wijeweera & Pinidiyaarachchi.

## Install

````

npm install convex-hull-wp

// Or for CLI usage

npm install convex-hull-wp -g

````

## API Documentation

Takes an array of `[x, y]` coordinates and returns the same

````js

    const convexHull = require('convex-hull-wp')

    const coords = [[42, 23], [46, 15], [51, 27], [34, 22], [54, 22]]

    convexHull(coords)

    // => [ [ 34, 22 ], [ 51, 27 ], [ 54, 22 ], [ 46, 15 ], [ 34, 22 ] ]

````

## CLI Documentation

Takes an input geojson file, and writes an output `Feature` `Polygon`

````

    convex-hull-wp --input /Data/in.geojson --output /Data/out.geojson

    // => Convex Hull Done

````

### CLI Options

`--input OR -i` **Required** The filepath of an geojson file. Eg `--input some_input.geojson`

`--output OR -o` The filepath to write the output to. Eg `--output hull.geojson`

`--stdout` Write the output to stdout rather than to file. If true the output file will not be written.

`--quiet or -q` Hides any non-error messages.

### Benchmarks

This library performs very well compared to equivalent js libraries.

````

// 10 points

// Convex Hull - WP x 1,631,956 ops/sec ±1.09% (93 runs sampled)

// monotone-convex-hull-2d x 631,516 ops/sec ±1.12% (87 runs sampled)

// convexhullJs x 712,072 ops/sec ±0.90% (91 runs sampled)

// convexHull x 569,445 ops/sec ±0.52% (94 runs sampled)

// - Fastest is Convex Hull - WP

// 1000 points

// Convex Hull - WP x 28,722 ops/sec ±0.93% (89 runs sampled)

// monotone-convex-hull-2d x 4,580 ops/sec ±0.61% (91 runs sampled)

// convexhullJs x 5,521 ops/sec ±0.88% (91 runs sampled)

// convexHull x 4,635 ops/sec ±0.87% (93 runs sampled)

// - Fastest is Convex Hull - WP

````

## Further Reading

[An Efficient Convex Hull Algorithm for a Planer Set of Points](https://github.com/rowanwins/convex-hull-wp/blob/master/KP_Paper.pdf) - by Wijeweera & Pinidiyaarachchi

Interestingly this algorithm could be sped up by applying parallel processing to each quadant of the hull.