Sphere Geometry in Swift

A core implementation of S2 Geometry in Swift.

At a Glance

The Cell structure is focusing on geometry calculation like providing coordinates of verticies, while the CellIdentifier is focusing on indexing features.

The CellCollection works as an ordered container of CellIdentifier, providing some set operations like union, difference and intersection.

Difference with C++ Implementation

Due to personal flavor, some of the concepts and naming in the original C++ implementation are changed.

Concept / Class Name	Change
Face	Zone
Face 0 ~ 6	Named enum cases africa asia north pacific america and south
Leaf-cell / IJ coordinate	LeafCoordinate
S2Cell	Cell
S2CellId	CellIdentifier
S2CellUnion	CellCollection
S2Point	CartesianCoordinate

S2Shape, S2Region and S2RegionCoverer are not implemented.

Usage

To use the SphereGeometry library in a SwiftPM project, add it to the dependencies for your package and your target:

let package = Package(
    // ...
    dependencies: [
        // ...
        .package(url: "https://github.com/lucka-me/sphere-geometry-swift", branch: "main"), // Since we don't have any release yet
    ],
    targets: [
        // ...
        .target(
            // ...
            dependencies: [
                // ...
                .product(name: "SphereGeometry", package: "sphere-geometry-swift"),
            ]
        )
    ]
)

Platform Availability

SphereGeometry depends on the simd module of Apple platform, therefore it's not available on Windows or Linux yet.