Merge branch 'main' into line_overlap_refactoring

README.md

@@ -1,9 +1,31 @@
-[![][image-1]][1]
-[![][image-2]][2]
+[![][image-1]][1]  
+[![][image-2]][2]  
+[![](https://img.shields.io/github/license/Outdooractive/gis-tools)](https://github.com/Outdooractive/gis-tools/blob/main/LICENSE)  
+[![](https://img.shields.io/github/v/release/Outdooractive/gis-tools?sort=semver&display_name=tag)](https://github.com/Outdooractive/gis-tools/releases) [![](https://img.shields.io/github/release-date/Outdooractive/gis-tools?display_date=published_at
+)](https://github.com/Outdooractive/gis-tools/releases)  
+[![](https://img.shields.io/github/issues/Outdooractive/gis-tools
+)](https://github.com/Outdooractive/gis-tools/issues) [![](https://img.shields.io/github/issues-pr/Outdooractive/gis-tools
+)](https://github.com/Outdooractive/gis-tools/pulls)  
+[![](https://img.shields.io/github/check-runs/Outdooractive/gis-tools/main)](https://github.com/Outdooractive/gis-tools/actions)
+
 
 # GISTools
 GIS tools for Swift, including a [GeoJSON][3] implementation and many algorithms ported from [https://turfjs.org][4].
 
+## Features
+
+- Supports the full [GeoJSON standard][6], with some exceptions (see [TODO.md][7])
+- Load and write GeoJSON objects from and to `[String:Any]`, `URL`, `Data` and `String`
+- Supports `Codable` and `SwiftData` (see below)
+- Supports EPSG:3857 (web mercator) and EPSG:4326 (geodetic) conversions
+- Supports WKT/WKB, also with different projections
+- Spatial search with a R-tree
+- Includes many spatial algorithms (ported from turf.js), and more to come
+- Has a helper for working with x/y/z map tiles (center/bounding box/resolution/…)
+- Can encode/decode Polylines
+- Pure Swift without external dependencies
+- Swift 6 ready
+
 ## Notes
 
 This package makes some assumptions about what is equal, i.e. coordinates that are inside of `1e-10` degrees are regarded as equal (that's μm precision and is probably overkill). See [GISTool.equalityDelta][5].
@@ -16,7 +38,7 @@ This package requires Swift 5.10 or higher (at least Xcode 14), and compiles on
 
 ```swift
 dependencies: [
-    .package(url: "https://github.com/Outdooractive/gis-tools", from: "1.7.0"),
+    .package(url: "https://github.com/Outdooractive/gis-tools", from: "1.8.2"),
 ],
 targets: [
     .target(name: "MyTarget", dependencies: [
@@ -25,23 +47,9 @@ targets: [
 ]
 ```
 
-## Features
-
-- Supports the full [GeoJSON standard][6], with some exceptions (see [TODO.md][7])
-- Load and write GeoJSON objects from and to `[String:Any]`, `URL`, `Data` and `String`
-- Supports `Codable` and `SwiftData` (see below)
-- Supports EPSG:3857 (web mercator) and EPSG:4326 (geodetic) conversions
-- Supports WKT/WKB, also with different projections
-- Spatial search with a R-tree
-- Includes many spatial algorithms (ported from turf.js), and more to come
-- Has a helper for working with x/y/z map tiles (center/bounding box/resolution/…)
-- Can encode/decode Polylines
-- Pure Swift without external dependencies
-- Swift 6 ready
-
 ## Usage
 
-Please see also the [API documentation][8].
+Please see also the [API documentation][8] (via Swift Package Index).
 
 ```swift
 import GISTools
@@ -877,7 +885,7 @@ Currently only two:
 - [mvt-postgis][130]: Creates vector tiles from Postgis databases
 
 # Contributing
-Please create an issue or open a pull request with a fix or enhancement.
+Please [create an issue](https://github.com/Outdooractive/gis-tools/issues) or [open a pull request](https://github.com/Outdooractive/gis-tools/pulls) with a fix or enhancement.
 
 # License
 MIT

Sources/GISTools/Algorithms/Center.swift

@@ -24,7 +24,11 @@ extension GeoJson {
     public var centroid: Point? {
         let allCoordinates = self.allCoordinates
 
-        guard !allCoordinates.isEmpty else { return nil }
+        guard allCoordinates.isNotEmpty else { return nil }
+
+        if allCoordinates.count == 1 {
+            return Point(allCoordinates[0])
+        }
 
         var sumLongitude: Double = 0.0
         var sumLatitude: Double = 0.0

Sources/GISTools/GeoJson/BoundingBox.swift

@@ -600,6 +600,13 @@ extension BoundingBox {
         return nil
     }
 
+    /// `true` if the receiver crosses the anti-meridian.
+    public var crossesAntiMeridian: Bool {
+        let boundingBox = self.normalized()
+
+        return boundingBox.southWest.longitude > boundingBox.northEast.longitude
+    }
+
 }
 
 // MARK: - Helpers

Sources/GISTools/Other/MapTile.swift

@@ -37,6 +37,10 @@ public struct MapTile: CustomStringConvertible, Sendable {
         ]
     }
 
+    public var siblings: [MapTile] {
+        parent.children
+    }
+
     public init(x: Int, y: Int, z: Int) {
         self.x = x
         self.y = y
@@ -52,6 +56,50 @@ public struct MapTile: CustomStringConvertible, Sendable {
         self.z = zoom
     }
 
+    // Ported from https://github.com/mapbox/tilebelt/blob/master/index.js
+    /// Initialize a tile from a bounding box.
+    /// The resulting tile will have a zoom level in `0...maxZoom`.
+    ///
+    /// - parameter boundingBox: The bounding box that the tile should completely contain
+    /// - parameter maxZoom: The maximum zoom level of the resulting tile, 0...32
+    public init(
+        boundingBox: BoundingBox,
+        maxZoom: Int = 32)
+    {
+        if boundingBox.crossesAntiMeridian {
+            self.init(x: 0, y: 0, z: 0)
+            return
+        }
+
+        let maxZoom = max(0, min(32, maxZoom))
+
+        let min = MapTile(coordinate: boundingBox.southWest, atZoom: 32)
+        let max = MapTile(coordinate: boundingBox.northEast, atZoom: 32)
+
+        var bestZ = -1
+        for z in 0 ..< maxZoom {
+            let mask = 1 << (32 - (z + 1))
+            if (min.x & mask) != (max.x & mask)
+                || (min.y & mask) != (max.y & mask)
+            {
+                bestZ = z
+                break
+            }
+        }
+        if bestZ == 0 {
+            self.init(x: 0, y: 0, z: 0)
+            return
+        }
+        if bestZ == -1 {
+            bestZ = maxZoom
+        }
+
+        self.init(
+            x: min.x >> (32 - bestZ),
+            y: min.y >> (32 - bestZ),
+            z: bestZ)
+    }
+
     public init?(string: String) {
         guard let components = string.components(separatedBy: "/").nilIfEmpty,
               components.count == 3,

Tests/GISToolsTests/Other/MapTileTests.swift

@@ -18,6 +18,25 @@ final class MapTileTests: XCTestCase {
 
     }
 
+    func testTileFromBoundingBox() throws {
+        let boundingBox1 = BoundingBox(
+            southWest: Coordinate3D(latitude: 46.5, longitude: 10.5),
+            northEast: Coordinate3D(latitude: 48.5, longitude: 11.0))
+        let boundingBox2 = BoundingBox(
+            southWest: Coordinate3D(latitude: 46.5, longitude: 10.5),
+            northEast: Coordinate3D(latitude: 48.5, longitude: 11.25))
+        let boundingBox3 = try XCTUnwrap(BoundingBox(coordinates: [Coordinate3D(latitude: 47.56, longitude: 10.22)]))
+
+        XCTAssertEqual(MapTile(boundingBox: boundingBox1), MapTile(x: 33, y: 22, z: 6))
+        XCTAssertEqual(MapTile(boundingBox: boundingBox2), MapTile(x: 8, y: 5, z: 4))
+
+        XCTAssertEqual(MapTile(boundingBox: boundingBox3), MapTile(x: 2269412997, y: 1500804469, z: 32))
+        XCTAssertEqual(MapTile(boundingBox: boundingBox3, maxZoom: 14), MapTile(x: 8657, y: 5725, z: 14))
+        XCTAssertEqual(MapTile(boundingBox: boundingBox3, maxZoom: 8), MapTile(x: 135, y: 89, z: 8))
+        XCTAssertEqual(MapTile(boundingBox: boundingBox3, maxZoom: 4), MapTile(x: 8, y: 5, z: 4))
+        XCTAssertEqual(MapTile(boundingBox: boundingBox3, maxZoom: 0), MapTile(x: 0, y: 0, z: 0))
+    }
+
     func testCenter() {
         let coordinate1 = MapTile(x: 138513, y: 91601, z: 18).centerCoordinate()
         XCTAssertEqual(coordinate1.latitude, 47.56031069944929, accuracy: 0.00001)