This is a small collection of geometry utilities to work with data in different projections, multiple polygons and polygon overlays:
- Parse
WKTand extract multiple polygons (implemented in Objective-C for performance's sake). - Convert multiple polygons into single
CGPathRefto be drawable withMapKitas a single polygon. - Convert from
Mercatorprojection andWGS84coordinate system.
// 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)))