GeoJSONKit+Turf

This package provides various geospatial extensions for GeoJSONKit. It is a fork of turf-swift, which itself is a partial Swift-port of Turf.js.

Requirements

GeoJSONKitTurf requires Xcode 14.x and supports the following minimum deployment targets:

• iOS 15 and above
• macOS 12 and above
• tvOS 15 and above
• visionOS 1.0 and above
• watchOS 8.0 and above

It's also compatible with Linux (and possibly other platforms), as long as you have Swift 5.7 (or above) installed.

Installation

Swift Package Manager

To install GeoJSONKitTurf using the Swift Package Manager, add the following package to the dependencies in your Package.swift file:

.package(name: "GeoJSONKitTurf", url: "https://github.com/maparoni/geojsonkit-turf", from: "0.3.0")

Then use:

import GeoJSONKitTurf

Available functionality

This is a partial port of Turf.js, which adds the following functionality to GeoJSONKit's GeoJSON:

Turf.js	GeoJSONKit-Turf
turf-along	GeoJSON.LineString.coordinateFromStart(distance:)
turf-area	GeoJSON.Polygon.area
turf-bbox-clip	GeoJSON.LineString.clipped(to:) GeoJSON.Polygon.clipped(to:)
turf-bearing	GeoJSON.Position.direction(to:) RadianCoordinate2D.direction(to:)
turf-bezier-spline	GeoJSON.LineString.bezier(resolution:sharpness:)
turf-boolean-point-in-polygon	GeoJSON.Polygon.contains(_:)
turf-center	GeoJSON.Geometry.center()
turf-center-of-mass	GeoJSON.Geometry.centerOfMass()
turf-centroid	GeoJSON.Geometry.centroid()
turf-circle	GeoJSON.Polygon(center:radius:)
turf-convex	GeoJSON.convexHull() Collection<GeoJSON.Position>.convexHull()
turf-destination	GeoJSON.Position.coordinate(at:facing:) RadianCoordinate2D.coordinate(at:facing:)
turf-distance	GeoJSON.Position.distance(to:) RadianCoordinate2D.distance(to:)
turf-helpers#degreesToRadians	GeoJSON.Degrees.toRadians()
turf-helpers#radiansToDegrees	GeoJSON.DegreesRadians.toDegrees()
turf-helpers#convertLength turf-helpers#convertArea	Measurement.converted(to:)
turf-length	GeoJSON.LineString.distance(from:to:)
turf-line-chunk	GeoJSON.LineString.chunked(length:) GeoJSON.Polygon.LinearRing.chunked(length:)
turf-line-intersect	GeoJSON.LineString.intersection(with:)
turf-line-slice	GeoJSON.LineString.sliced(from:to:)
turf-line-slice-along	GeoJSON.LineString.trimmed(from:distance:) GeoJSON.LineString.trimmed(from:to:)
turf-midpoint	mid(_:_:)
turf-nearest-point-on-line	GeoJSON.LineString.closestCoordinate(to:)
turf-point-on-feature	GeoJSON.Geometry.nearestPoint(to:) GeoJSON.Polygon.nearestPoint(to:)
turf-polygon-smooth	GeoJSON.Polygon.smooth(iterations:)
turf-union	Not provided, but see ASPolygonKit
turf-simplify	GeoJSON.simplify(options:)

Additionally, it adds the following features, which do not have a direct equivalent in turf.js:

• GeoJSON.Direction.difference(from:)
• GeoJSON.Direction.wrap(min:max:)
• GeoJSON.LineString.frechetDistance(to:): Determines the Fréchet distance between two line strings, which is a measure of their similarity.
• GeoJSON.GeometryObject(splittingWhenCrossingAntiMeridian:): Breaks up a LineString or Polygon into two when crossing the anti-meridian.

CLI

Comes with a mini-CLI geokitten with these commands:

• geokitten simplify $input to simplify a GeoJSON

Installation

Via SPM

First clone or download the repository, then run this:

swift build -c release
sudo cp .build/release/geokitten /usr/local/bin/geokitten

Via Mint

mint install maparoni/GeoJSONKit-Turf@main

If you get a permissions error, check this Mint issue.