dastrobu/geodesic

Table of Contents

• Installation

- Swift Package Manager

• Implementation Details
• Convergence and Tolerance
• WGS 84 and other Ellipsoids
• Known Issues

Installation

At least clang-3.6 is required. On linux one might need to install it explicitly. There are no dependencies on macOS.

Swift Package Manager

let package = Package(
    dependencies: [
        .package(url: "https://github.com/dastrobu/geodesic.git", from: "1.5.0"),
    ]
)

Implementation Details

This Swift package is a wrapper for the C implementation of the geodesic routines in GeographicLib. The goal of this Swift package is to make some algorithms from GeographicLib available to the Swift world. Alternatively one can employ the package vincenty which is a much simpler solver for the inverse geodesic problem, completely written in Swift. Vincenty's formulae does, however, have some convergence problems in rare cases and may not give the same accuracy as Karney's algorithm.

Convergence and Tolerance

The computation does always converge and is said to compute up to machine precision. See documentation of GeographicLib for details.

WGS 84 and other Ellipsoids

By default the WGS 84 ellipsoid is employed, but different parameters can be specified, e.g. for the GRS 80 ellipsoid.

distance((lat: Double.pi / 2, lon: 0), (lat: -Double.pi / 2, lon: 0), 
            ellipsoid (a: 6378137.0, f: 1/298.257222100882711))

Known Issues

• Compilation with gcc on Linux does not work. swift build fails. No problems with clang on Linux.

Package Metadata

Repository: dastrobu/geodesic

Stars: 6

Forks: 1

Open issues: 0

Default branch: main

Primary language: c

License: MIT

Topics: distance-calculation, geodesic, geodesics, swift, swift-4, swift-5, swift-library, swift-linux, vincenty, vincenty-formula

README: README.md