Geometry Utilities

This is a small collection of geometry utilities to work with data in different projections, multiple polygons and polygon overlays:

• Parse WKT and extract multiple polygons (implemented in Objective-C for performance’s sake).
• Convert multiple polygons into single CGPathRef to be drawable with MapKit as a single polygon.
• Convert from Mercator projection and WGS84 coordinate system.

API

// Extract polygons from a WKT string
let wkt = "MULTIPOLYGON(((0.0 0.0, 0.0 1.0, 1.0 1.0, 1.0 0.0)))"
let polygons = WKT.polygons(in: wkt)
let polygon = polygons.first
polygon?.coordinates() // (0, 0), (0, 1), (1, 1), (1, 0), (0, 0)

// Serialize polygons into a WKT string
let polygon = MKPolygon(
    coordinates: [
        CLLocationCoordinate2D(
            latitude: 0,
            longitude: 0
        ),
        CLLocationCoordinate2D(
            latitude: 1,
            longitude: 0
        ),
        CLLocationCoordinate2D(
            latitude: 1,
            longitude: 1
        ),
        CLLocationCoordinate2D(
            latitude: 0,
            longitude: 1
        )
    ]
)
polygon.wktString() // MULTIPOLYGON(((0.0 0.0, 0.0 1.0, 1.0 1.0, 1.0 0.0)))