sfera

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sfera models RFC 7946 GeoJSON as Swift value types. The rules of the format live in the types:

  • Coordinates are validated the moment a Position is created.
  • A line string needs two positions, and a ring three vertices. The compiler checks both.
  • Rings close themselves, and polygons follow the right-hand rule automatically.
  • Large integer identifiers and properties survive a round trip exactly.

Every type is Codable, Sendable and Hashable. sfera has no third-party dependencies and uses only the Swift standard library.

Quick start Link to heading

import Foundation
import sfera

let rome = try Position(latitude: 41.9028, longitude: 12.4964)
let city = Feature(id: "rome", geometry: .point(rome), properties: ["name": "Rome"])

let data = try JSONEncoder().encode(FeatureCollection([city]))
// {"type":"FeatureCollection","features":[{"type":"Feature","id":"rome","geometry":{"type":"Point","coordinates":[12.4964,41.9028]},"properties":{"name":"Rome"}}]}

let document = try JSONDecoder().decode(GeoJSON.self, from: data)

Installation Link to heading

sfera requires Swift 6.4. It runs on iOS, macOS, watchOS and tvOS 26, on Linux, and on WebAssembly (WASI). Add it with Swift Package Manager:

dependencies: [
    .package(url: "https://github.com/csanfilippo/sfera.git", from: "0.1.0")
]

Learn more Link to heading

  • The full guide, covering geometries, features, decoding rules and output, is on GitHub