Ported the turf-boolean-point-in-polygon function to Turf Swift.

Uses the identical algorithm as used in Turf.js. https://github.com/Turfjs/turf/blob/e53677b0931da9e38bb947da448ee7404adc369d/packages/turf-boolean-point-in-polygon/index.ts
mapbox · Sep 18, 2018 · d679d07 · d679d07
1 parent 5f35431
commit d679d07
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diff --git a/README.md b/README.md
@@ -73,6 +73,7 @@ Turf.js | Turf-swift
 ----|----
 [turf-along](https://github.com/Turfjs/turf/tree/master/packages/turf-along/) | `LineString.coordinateFromStart(distance:)`
 [turf-area](https://github.com/Turfjs/turf/blob/master/packages/turf-area/) | `Polygon.area`
+[turf-boolean-point-in-polygon](https://github.com/Turfjs/turf/tree/master/packages/turf-boolean-point-in-polygon) | `Polygon.contains(point:ignoreBoundary:)`
 [turf-destination](https://github.com/Turfjs/turf/tree/master/packages/turf-destination/) | `CLLocationCoordinate2D.coordinate(at:facing:)`<br>`RadianCoordinate2D.coordinate(at:facing:)`
 [turf-distance](https://github.com/Turfjs/turf/tree/master/packages/turf-distance/) | `CLLocationCoordinate2D.distance(to:)`<br>`RadianCoordinate2D.distance(to:)`
 [turf-helpers#polygon](https://github.com/Turfjs/turf/tree/master/packages/turf-helpers/#polygon) | `Polygon(outerRing:innerRings:)`

diff --git a/Sources/Turf/BoundingBox.swift b/Sources/Turf/BoundingBox.swift
@@ -0,0 +1,32 @@
+import Foundation
+#if !os(Linux)
+import CoreLocation
+#endif
+
+public class BoundingBox {
+
+    public init?(points: [CLLocationCoordinate2D]?) {
+        guard points?.count ?? 0 > 0 else {
+            return nil
+        }
+        (minLat, maxLat, minLon, maxLon) = points!
+            .reduce((minLat: 0, maxLat: 0, minLon: 0, maxLon: 0)) { (result, coordinate) -> (minLat: Double, maxLat: Double, minLon: Double, maxLon: Double) in
+                let minLat = min(coordinate.latitude, result.0)
+                let maxLat = max(coordinate.latitude, result.1)
+                let minLon = min(coordinate.longitude, result.2)
+                let maxLon = max(coordinate.longitude, result.3)
+                return (minLat: minLat, maxLat: maxLat, minLon: minLon, maxLon: maxLon)
+        }
+    }
+
+    public func contains(point: CLLocationCoordinate2D) -> Bool {
+        return minLat < point.latitude && maxLat > point.latitude && minLon < point.longitude && maxLon > point.longitude
+    }
+
+    // MARK: - Private
+
+    let minLat: Double
+    let maxLat: Double
+    let minLon: Double
+    let maxLon: Double
+}
diff --git a/Sources/Turf/Polygon.swift b/Sources/Turf/Polygon.swift
@@ -59,3 +59,32 @@ extension Polygon {
             .reduce(0, +)
     }
 }
+
+extension Polygon {
+
+    /**
+     * Determines if the given point falls within the polygon and outside of its interior rings.
+     * The optional parameter `ignoreBoundary` will result in the method returning true if the given point
+     * lies on the boundary line of the polygon or its interior rings.
+     *
+     * Ported from: https://github.com/Turfjs/turf/blob/e53677b0931da9e38bb947da448ee7404adc369d/packages/turf-boolean-point-in-polygon/index.ts#L31-L75
+     */
+    public func contains(point: CLLocationCoordinate2D, ignoreBoundary: Bool = false) -> Bool {
+        let bbox = BoundingBox(points: self.coordinates.first)
+        guard bbox?.contains(point: point) ?? false else {
+            return false
+        }
+        guard self.outerRing.contains(point: point, ignoreBoundary: ignoreBoundary) else {
+            return false
+        }
+        if let innerRings = innerRings {
+            for ring in innerRings {
+                if ring.contains(point: point, ignoreBoundary: ignoreBoundary) {
+                    return false
+                }
+            }
+        }
+        return true
+    }
+}
+
diff --git a/Sources/Turf/Ring.swift b/Sources/Turf/Ring.swift
@@ -53,3 +53,44 @@ public struct Ring {
         return area
     }
 }
+
+extension Ring {
+    /**
+     * Determines if the given point falls within the ring.
+     * The optional parameter `ignoreBoundary` will result in the method returning true if the given point
+     * lies on the boundary line of the ring.
+     *
+     * Ported from: https://github.com/Turfjs/turf/blob/e53677b0931da9e38bb947da448ee7404adc369d/packages/turf-boolean-point-in-polygon/index.ts#L77-L108
+     */
+    public func contains(point: CLLocationCoordinate2D, ignoreBoundary: Bool = false) -> Bool {
+        var ring: ArraySlice<CLLocationCoordinate2D>!
+        var isInside = false
+        if coordinates.first == coordinates.last {
+            ring = coordinates.prefix(coordinates.count - 1)
+        }
+        else {
+             ring = coordinates.prefix(coordinates.count)
+        }
+        var i = 0
+        var j = ring.count - 1
+        while i < ring.count {
+            let xi = ring[i].longitude
+            let yi = ring[i].latitude
+            let xj = ring[j].longitude
+            let yj = ring[j].latitude
+            let onBoundary = (point.latitude * (xi - xj) + yi * (xj - point.longitude) + yj * (point.longitude - xi) == 0) &&
+                ((xi - point.longitude) * (xj - point.longitude) <= 0) && ((yi - point.latitude) * (yj - point.latitude) <= 0)
+            if onBoundary {
+                return !ignoreBoundary
+            }
+            let intersect = ((yi > point.latitude) != (yj > point.latitude)) &&
+                (point.longitude < (xj - xi) * (point.latitude - yi) / (yj - yi) + xi);
+            if (intersect) {
+                isInside = !isInside;
+            }
+            j = i
+            i = i + 1
+        }
+        return isInside
+    }
+}
diff --git a/Tests/TurfTests/PolygonTests.swift b/Tests/TurfTests/PolygonTests.swift
@@ -28,4 +28,49 @@ class PolygonTests: XCTestCase {
         XCTAssert(decoded.geometry.outerRing.coordinates.count == 5)
         XCTAssert(decoded.geometry.innerRings!.first?.coordinates.count == 5)
     }
+
+    func testPolygonContains() {
+        let coordinate = CLLocationCoordinate2D(latitude: 44, longitude: -77)
+        let polygon = Polygon([[
+            CLLocationCoordinate2D(latitude: 41, longitude: -81),
+            CLLocationCoordinate2D(latitude: 47, longitude: -81),
+            CLLocationCoordinate2D(latitude: 47, longitude: -72),
+            CLLocationCoordinate2D(latitude: 41, longitude: -72),
+            CLLocationCoordinate2D(latitude: 41, longitude: -81),
+            ]])
+        XCTAssertTrue(polygon.contains(point: coordinate))
+    }
+
+    func testPolygonDoesNotContain() {
+        let coordinate = CLLocationCoordinate2D(latitude: 44, longitude: -77)
+        let polygon = Polygon([[
+            CLLocationCoordinate2D(latitude: 41, longitude: -51),
+            CLLocationCoordinate2D(latitude: 47, longitude: -51),
+            CLLocationCoordinate2D(latitude: 47, longitude: -42),
+            CLLocationCoordinate2D(latitude: 41, longitude: -42),
+            CLLocationCoordinate2D(latitude: 41, longitude: -51),
+            ]])
+        XCTAssertFalse(polygon.contains(point: coordinate))
+    }
+
+    func testPolygonDoesNotContainWithHole() {
+        let coordinate = CLLocationCoordinate2D(latitude: 44, longitude: -77)
+        let polygon = Polygon([
+            [
+                CLLocationCoordinate2D(latitude: 41, longitude: -81),
+                CLLocationCoordinate2D(latitude: 47, longitude: -81),
+                CLLocationCoordinate2D(latitude: 47, longitude: -72),
+                CLLocationCoordinate2D(latitude: 41, longitude: -72),
+                CLLocationCoordinate2D(latitude: 41, longitude: -81),
+            ],
+            [
+                CLLocationCoordinate2D(latitude: 43, longitude: -76),
+                CLLocationCoordinate2D(latitude: 43, longitude: -78),
+                CLLocationCoordinate2D(latitude: 45, longitude: -78),
+                CLLocationCoordinate2D(latitude: 45, longitude: -76),
+                CLLocationCoordinate2D(latitude: 43, longitude: -76),
+            ],
+        ])
+        XCTAssertFalse(polygon.contains(point: coordinate))
+    }
 }
diff --git a/Turf.xcodeproj/project.pbxproj b/Turf.xcodeproj/project.pbxproj
@@ -118,6 +118,10 @@
 		C46809D721241B5100BAD5E1 /* featurecollection-no-properties.geojson in Resources */ = {isa = PBXBuildFile; fileRef = C46809D52124199500BAD5E1 /* featurecollection-no-properties.geojson */; };
 		C46809D821249E8F00BAD5E1 /* featurecollection-no-properties.geojson in Resources */ = {isa = PBXBuildFile; fileRef = C46809D52124199500BAD5E1 /* featurecollection-no-properties.geojson */; };
 		C46809D921249E9700BAD5E1 /* featurecollection-no-properties.geojson in Resources */ = {isa = PBXBuildFile; fileRef = C46809D52124199500BAD5E1 /* featurecollection-no-properties.geojson */; };
+		CE2EB998214C246A00915A30 /* BoundingBox.swift in Sources */ = {isa = PBXBuildFile; fileRef = CE2EB997214C246A00915A30 /* BoundingBox.swift */; };
+		CE2EB999214C247100915A30 /* BoundingBox.swift in Sources */ = {isa = PBXBuildFile; fileRef = CE2EB997214C246A00915A30 /* BoundingBox.swift */; };
+		CE2EB99A214C247100915A30 /* BoundingBox.swift in Sources */ = {isa = PBXBuildFile; fileRef = CE2EB997214C246A00915A30 /* BoundingBox.swift */; };
+		CE2EB99B214C247200915A30 /* BoundingBox.swift in Sources */ = {isa = PBXBuildFile; fileRef = CE2EB997214C246A00915A30 /* BoundingBox.swift */; };
 		DA39EB6E20101F99004D87F7 /* Turf.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = DA39EB6520101F98004D87F7 /* Turf.framework */; };
 		DA39EB7C20101FB9004D87F7 /* Turf.h in Headers */ = {isa = PBXBuildFile; fileRef = 3547ECEF200C3C78009DA062 /* Turf.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		DA39EB7D20101FCD004D87F7 /* CoreLocation.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3547ECF0200C3C78009DA062 /* CoreLocation.swift */; };
@@ -197,6 +201,7 @@
 		35ECAF2E20974A1800DC3BC3 /* Geometry.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Geometry.swift; sourceTree = "<group>"; };
 		35ECAF352099EC0700DC3BC3 /* FeatureIdentifier.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = FeatureIdentifier.swift; sourceTree = "<group>"; };
 		C46809D52124199500BAD5E1 /* featurecollection-no-properties.geojson */ = {isa = PBXFileReference; lastKnownFileType = text; path = "featurecollection-no-properties.geojson"; sourceTree = "<group>"; };
+		CE2EB997214C246A00915A30 /* BoundingBox.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BoundingBox.swift; sourceTree = "<group>"; };
 		DA39EB6520101F98004D87F7 /* Turf.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Turf.framework; sourceTree = BUILT_PRODUCTS_DIR; };
 		DA39EB6D20101F99004D87F7 /* TurfTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = TurfTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		DA94249B2010283900CDB4E6 /* Turf.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Turf.framework; sourceTree = BUILT_PRODUCTS_DIR; };
@@ -263,6 +268,7 @@
 			children = (
 				3547ECEF200C3C78009DA062 /* Turf.h */,
 				3547ECF2200C3C78009DA062 /* Info.plist */,
+				CE2EB997214C246A00915A30 /* BoundingBox.swift */,
 				3502F795201F53FC00399EFE /* Codable.swift */,
 				3547ECF0200C3C78009DA062 /* CoreLocation.swift */,
 				35B56E9120DAF66A00C4923D /* FeatureCollection.swift */,
@@ -679,6 +685,7 @@
 				35B56E7520DAF47D00C4923D /* Polygon.swift in Sources */,
 				35B56E7F20DAF4E700C4923D /* LineString.swift in Sources */,
 				35B56E7A20DAF4BF00C4923D /* Point.swift in Sources */,
+				CE2EB999214C247100915A30 /* BoundingBox.swift in Sources */,
 				35B56E7020DAF41F00C4923D /* Ring.swift in Sources */,
 				3502F797201F53FC00399EFE /* Codable.swift in Sources */,
 				35B56E8E20DAF59700C4923D /* MultiPolygon.swift in Sources */,
@@ -717,6 +724,7 @@
 				35B56E7420DAF47D00C4923D /* Polygon.swift in Sources */,
 				35B56E7E20DAF4E700C4923D /* LineString.swift in Sources */,
 				35B56E7920DAF4BF00C4923D /* Point.swift in Sources */,
+				CE2EB998214C246A00915A30 /* BoundingBox.swift in Sources */,
 				35B56E6F20DAF41F00C4923D /* Ring.swift in Sources */,
 				3502F796201F53FC00399EFE /* Codable.swift in Sources */,
 				35B56E8D20DAF59700C4923D /* MultiPolygon.swift in Sources */,
@@ -755,6 +763,7 @@
 				35B56E7620DAF47D00C4923D /* Polygon.swift in Sources */,
 				35B56E8020DAF4E700C4923D /* LineString.swift in Sources */,
 				35B56E7B20DAF4BF00C4923D /* Point.swift in Sources */,
+				CE2EB99A214C247100915A30 /* BoundingBox.swift in Sources */,
 				35B56E7120DAF41F00C4923D /* Ring.swift in Sources */,
 				3502F798201F53FC00399EFE /* Codable.swift in Sources */,
 				35B56E8F20DAF59700C4923D /* MultiPolygon.swift in Sources */,
@@ -793,6 +802,7 @@
 				35B56E7720DAF47D00C4923D /* Polygon.swift in Sources */,
 				35B56E8120DAF4E700C4923D /* LineString.swift in Sources */,
 				35B56E7C20DAF4BF00C4923D /* Point.swift in Sources */,
+				CE2EB99B214C247200915A30 /* BoundingBox.swift in Sources */,
 				35B56E7220DAF41F00C4923D /* Ring.swift in Sources */,
 				3502F799201F53FC00399EFE /* Codable.swift in Sources */,
 				35B56E9020DAF59700C4923D /* MultiPolygon.swift in Sources */,