Merge pull request #34 from Outdooractive/geojson_projection

#33: Adds support for projections

Sources/GISTools/Extensions/ArrayExtensions.swift

@@ -121,8 +121,11 @@ extension Array {
 
     /// Returns the array's elements pairwise, with every element only once in the result.
     /// For arrays with uneven length, the last element will be skipped.
+    ///
+    /// ```
     /// let a = [1, 2, 3, 4, 5]
     /// a.distinctPairs() -> [(1, 2), (3, 4)]
+    /// ```
     func distinctPairs() -> [(first: Element, second: Element)] {
         guard !isEmpty else { return [] }
 
@@ -133,8 +136,11 @@ extension Array {
     }
 
     /// Returns the array's elements pairwise, where each pair overlaps the previous pair.
+    ///
+    /// ```
     /// let a = [1, 2, 3, 4, 5]
     /// a.overlappingPairs() -> [(1, 2), (2, 3), (3, 4), (4, 5)]
+    /// ```
     func overlappingPairs() -> [(first: Element, second: Element)] {
         guard !isEmpty else { return [] }
 
@@ -169,4 +175,9 @@ extension Array {
         return self
     }
 
+    /// A Boolean value indicating whether the collection is not empty.
+    var isNotEmpty: Bool {
+        !isEmpty
+    }
+
 }

Sources/GISTools/Extensions/DataExtensions.swift

@@ -14,6 +14,7 @@ extension Data {
             .compactMap { UInt8($0, radix: 16) }
 
         guard hex.count / bytes.count == 2 else { return nil }
+
         self.init(bytes)
     }
 

Sources/GISTools/GISTool.swift

@@ -2,8 +2,6 @@
 import CoreLocation
 #endif
 
-// MARK: GISTool
-
 /// Some constants used in this library.
 public enum GISTool {
 
@@ -16,6 +14,9 @@ public enum GISTool {
     /// Length of the equator, in meters.
     public static let earthCircumference: CLLocationDistance = 40_075_016.6855785
 
+    /// Mercator projection origin shift.
+    public static let originShift = 2.0 * Double.pi * GISTool.equatorialRadius / 2.0 // 20037508.342789244
+
     /// The accuracy for testing what is equal.
     public static let equalityDelta: Double = 1e-10