Polyline encoder / decoder in Swift

1. Features
2. Requirements
3. Integration
4. Usage
5. Notes
6. Contributors
7. License

Features

• Encode a CLLocationCoordinate2D array to a polyline
• Decode a polyline to an array of CLLocationCoordinate2D
• Encode a CLLocation array to a polyline
• Decode a polyline to an array of CLLocation
• Encode/Decode associated levels (optional)
• 100% Unit Test Coverage
• Complete Documentation
• Continuous integration with Travis CI
• CocoaPod available
• Convert to MKPolyline

Planned for future releases

• Convert to GMSPolyline
• Example project
• Filter locations available at a specific level

Planned when support is available :

• Code Coverage with Coveralls

Requirements

• Xcode 11+
• iOS 12.0+ / Mac OS X 10.14+ / tvOS 12.0+ / watchOS 5.0+ / Linux
• Swift 5.0

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Integration

To use this library in your project you can use CocoaPods, Carthage, Swift Package Manager, and/or integrate it manually :

CocoaPods

You can integrate Polyline in your Podfile like this:

pod 'Polyline', '~> 5.0'

Carthage

You can integrate Polyline in your Cartfile like this:

github "raphaelmor/Polyline" ~> 5.0

Swift Package Manager

To integrate Polyline into an application using Swift Package Manager within Xcode:

1. Go to File ‣ Swift Packages ‣ Add Package Dependency.
2. Enter https://github.com/raphaelmor/Polyline.git as the package repository and click Next.
3. Set Rules to Version, Up to Next Major, and enter 5.0.2 as the minimum version requirement. Click Next.

Or to integrate Polyline into another Swift package, add the following package to the dependencies in your Package.swift file:

.package(url: "https://github.com/raphaelmor/Polyline.git", from: "5.0.2")

Manual

To install Polyline manually, add Polyline.xcodeproj to an Xcode workspace, then link your application to Polyline.framework.

It is technically possible to install Polyline by adding Polyline.swift and CoreLocation.swift directly to your project, but this approach is not recommended as it may omit important files in the future.

Usage

Polyline Encoding

Using [CLLocationCoordinate2D] (recommended) :

let coordinates = [CLLocationCoordinate2D(latitude: 40.2349727, longitude: -3.7707443),
CLLocationCoordinate2D(latitude: 44.3377999, longitude: 1.2112933)]

let polyline = Polyline(coordinates: coordinates)
let encodedPolyline: String = polyline.encodedPolyline

// Or for a functional approach :
let encodedPolyline: String = encodeCoordinates(coordinates)

Using [CLLocation] :

let locations = [CLLocation(latitude: 40.2349727, longitude: -3.7707443),
CLLocation(latitude: 44.3377999, longitude: 1.2112933)]

let polyline = Polyline(locations: locations)
let encodedPolyline: String = polyline.encodedPolyline

// Or for a functional approach :
let encodedPolyline: String = encodeLocations(locations)

You can encode levels too :

let levels: [UInt32] = [0,1,2,255]

let polyline = Polyline(coordinates: coordinates, levels: levels)
let encodedLevels: String? = polyline.encodedLevels

// Or for a functional approach :
let encodedLevels: String = encodedLevels(levels)

Polyline Decoding

You can decode to [CLLocationCoordinate2D] (recommended) :

let polyline = Polyline(encodedPolyline: "qkqtFbn_Vui`Xu`l]")
let decodedCoordinates: [CLLocationCoordinate2D]? = polyline.coordinates

// Or for a functional approach :
let coordinates: [CLLocationCoordinate2D]? = decodePolyline("qkqtFbn_Vui`Xu`l]")

You can also decode to [CLLocation] :

let polyline = Polyline(encodedPolyline: "qkqtFbn_Vui`Xu`l]")
let decodedLocations: [CLLocation]? = polyline.locations

// Or for a functional approach :
let locations: [CLLocation]? = decodePolyline("qkqtFbn_Vui`Xu`l]")

You can decode levels too :

let polyline = Polyline(encodedPolyline: "qkqtFbn_Vui`Xu`l]", encodedLevels: "BA")
let decodedLevels: [UInt32]? = polyline.levels

// Or for a functional approach :
let levels: [UInt32]? = decodeLevels("BA")

Polyline Precision

Default precision is 1e5 : 0.12345 (5 digit precision used by Google), but you can specify your own precision in all API methods (and functions).

// OSRM uses a 6 digit precision
let polyline = Polyline(encodedPolyline: "ak{hRak{hR", precision: 1e6)

Notes

This library tries to have consistent results with polylines generated by the Google Maps iOS SDK. The online tool for encoding polylines has some minor inconsistencies regarding rounding (for example, 0.000015 is rounded to 0.00002 for latitudes, but 0.00001 for longitudes).

This codes tries to adhere to the GitHub Swift Style Guide

Contributors

• Raphaël Mor (@raphaelmor): Creator
• Tom Taylor: Maintainer
• Minh Nguyễn: Maintainer

License

Polyline is released under an MIT license. See LICENSE.txt for more information.