SwiftSimplify is a tiny high-performance Swift polyline simplification library ported from Javascript's Simplify.js. Original work come from Leaflet, a JS interactive maps library by Vladimir Agafonkin.

It uses a combination of Douglas-Peucker and Radial Distance algorithms. Works both on browser and server platforms.

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Why

Polyline simplification dramatically reduces the number of points in a polyline while retaining its shape, giving a huge performance boost when processing it and also reducing visual noise. For example, it's essential when rendering a 70k-points line chart or a map route in the browser using MapKit.

Requirements

• iOS 8.0, watchOS 2.0, tvOS 9.0
• Swift 5.x+

Communication

• If you found a bug, open an issue.
• If you have a feature request, open an issue.
• If you want to contribute, submit a pull request.

Installation

SwiftSimplify is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "SwiftSimplify"

Usage

Usage is pretty straightforward: in fact you need just call the SwiftSimplify's class method simplify by passing your configuration:

let allPoints: [Point2DRepresentable] = ...
let simplifiedPoints = SwiftSimplify.simplify(allPoints, tolerance: tolerance)

Allowed parameters are:

• points: An array of points. SwiftSimplify supports Swift's generic so you can pass an array of objects which are conforms to Point2DRepresentable protocol (both CGPoint and CLLocationCoordinate2D objects supports it).
• tolerance: (1 by default) Affects the amount of simplification (in the same metric as the point coordinates)
• highQuality: (false by default) Excludes distance-based preprocessing step which leads to highest quality simplification but runs ~10-20 times slower.

Author

Daniele Margutti, [email protected]

You can reach me on twitter @danielemargutti.

My web site is danielemargutti.com

License

SwiftSimplify is available under the MIT license. See the LICENSE file for more info.