SwiftGpx

SwiftGpx is a library for parsing and writing GPX data.

SwiftGpx powers GPX File Editor, which is available for iPhone in the App Store.

Example

To run the example playground clone the repo, run pod install in the Example directory and open the Example.xcworkspace workspace. The Example playground (first element in the Project Navigator) contains all the examples from below.

Import SwiftGpx

import SwiftGpx

some examples below reqire you to import

import CoreLocation

Instantiating GPX objects...

...with an Array of CLLocation instances:

let locations: [CLLocation] = [
    CLLocation(lat: 38.1237270, lon: -119.4670500, alt: 2899.8, timestamp: "2021-06-03T20:25:26Z"),
    CLLocation(lat: 38.1237330, lon: -119.4670490, alt: 2899.8, timestamp: "2021-06-03T20:25:27Z"),
    CLLocation(lat: 38.1237360, lon: -119.4670510, alt: 2899.8, timestamp: "2021-06-03T20:25:28Z"),
    CLLocation(lat: 38.1237360, lon: -119.4670500, alt: 2899.8, timestamp: "2021-06-03T20:25:29Z"),
    CLLocation(lat: 38.1237360, lon: -119.4670500, alt: 2899.8, timestamp: "2021-06-03T20:25:30Z"),
    CLLocation(lat: 38.1237360, lon: -119.4670510, alt: 2899.8, timestamp: "2021-06-03T20:25:31Z")
].compactMap { $0 }

let gpx = GPX(name: "My Track", locations: locations)

...with the xml contents of a GPX file

let gpxString = """
<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<gpx
    xmlns="http://www.topografix.com/GPX/1/1" creator="SwiftGpx by Axel Ancona Esselmann" version="1.1"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd">
    <trk>
        <name>My Track</name>
        <trkseg>
            <trkpt lat="38.123727" lon="-119.46705">
                <ele>2899.8</ele>
                <time>2021-06-03T20:25:26Z</time>
            </trkpt>
            <trkpt lat="38.123733" lon="-119.467049">
                <ele>2899.8</ele>
                <time>2021-06-03T20:25:27Z</time>
            </trkpt>
        </trkseg>
        <trkseg>
            <trkpt lat="38.123736" lon="-119.467051">
                <ele>2899.8</ele>
                <time>2021-06-03T20:25:28Z</time>
            </trkpt>
            <trkpt lat="38.123736" lon="-119.46705">
                <ele>2899.8</ele>
                <time>2021-06-03T20:25:29Z</time>
            </trkpt>
        </trkseg>
    </trk>
</gpx>
"""

let gpx = GPX(xmlString: gpxString)

...with the name of a file that is located in the Bundle

let gpx = GPX(fileName: "example", fileExtension: "gpx")

...with a local file resource

if let localResource = Bundle.main.url(forResource: "example", withExtension: "gpx") {
    let gpx = GPX(localResource: localResource)
    ...
}

Converting GPX content to...

...a GPX String

let gpx = GPX(name: "My Track", locations: locations)
let xmlString = gpx.xmlString

... Data, which is encoded to be stored or transmitted as a GPX file

let gpx = GPX(name: "My Track", locations: locations)
let xmlData = gpx.data

Serializing/Deserializing using Codabl

the JSONEncoder settings below will produce output like the following:

{
  "name" : "My Track",
  "track_segments" : [
    [
      {
        "lat" : 38.123727000000002,
        "lon" : -119.46705,
        "ele" : 2899.8000000000002,
        "date" : "2021-06-03T20:25:26Z"
      },
      {
        "lat" : 38.123733000000001,
        "lon" : -119.467049,
        "ele" : 2899.8000000000002,
        "date" : "2021-06-03T20:25:27Z"
      }
    ],
    [
      {
        "lat" : 38.123736000000001,
        "lon" : -119.46705,
        "ele" : 2899.8000000000002,
        "date" : "2021-06-03T20:25:29Z"
      },
      {
        "lat" : 38.123736000000001,
        "lon" : -119.46705,
        "ele" : 2899.8000000000002,
        "date" : "2021-06-03T20:25:30Z"
      }
    ]
  ]
}

Encoding using JSONEncoder

let gpx = GPX(name: "My Track", locations: locations)

let encoder = JSONEncoder()
encoder.dateEncodingStrategy = .iso8601
encoder.keyEncodingStrategy = .convertToSnakeCase
encoder.outputFormatting = [.prettyPrinted]
let encoded = try encoder.encode(gpx)
let encodedString = String(data: encoded, encoding: .utf8)

Decoding using JSONDecoder

let decoder = JSONDecoder()
decoder.dateDecodingStrategy = .iso8601
decoder.keyDecodingStrategy = .convertFromSnakeCase
// uses the encoded data from the previous example
let gpxFromJson = try decoder.decode(GPX.self, from: encoded) 

Serializing into a dictionary that keeps the structure of the XML intact

the gpxJson propperty will produce a dictionary that can be serialized to look like the following:

{
    "gpx": {
        "name": "My Track",
        "trkseg_elements": [
            [
                {
                    "lon": -119.46705,
                    "lat": 38.123727000000002,
                    "ele": 2899.8000000000002,
                    "time": "2021-06-03T13:25:26-0700"
                },
                {
                    "time": "2021-06-03T13:25:27-0700",
                    "lon": -119.467049,
                    "lat": 38.123733000000001,
                    "ele": 2899.8000000000002
                }
            ]
        ]
    }
}

let gpx = GPX(name: "My Track", locations: locations)
let dictionary: [String: Any] = gpx.gpxJson

You can get a JSON string using

let gpx = GPX(name: "My Track", locations: locations)
let data = try JSONSerialization.data(withJSONObject: gpx.gpxJson, options: [.prettyPrinted])
let jsonString = String(data: data, encoding: .utf8)

Installation

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

pod 'SwiftGpx'

Author

anconaesselmann, axel@anconaesselmann.com

License

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