Fix parameter names in GeodesicLine.

Author: scottrhoyt

README.md

@@ -111,8 +111,10 @@ For efficient calculations of multiple points along a geodesic:
 ```swift
 // Create a geodesic line
 let line = geodesic.inverseLine(
-    latitude1: 40.64, longitude1: -73.78,  // JFK
-    latitude2: 1.36, longitude2: 103.99     // Singapore
+    startLatitude: 40.64, 
+    startLongitude: -73.78,  // JFK
+    endlatitude: 1.36, 
+    endLongitude: 103.99     // Singapore
 )
 
 // Calculate waypoints

Sources/GeographicLib/GeodesicLine.swift

@@ -202,20 +202,25 @@ public extension Geodesic {
     /// Create a geodesic line from an inverse problem.
     ///
     /// - Parameters:
-    ///   - latitude1: First point latitude in degrees [-90, 90]
-    ///   - longitude1: First point longitude in degrees [-180, 180]
-    ///   - latitude2: Second point latitude in degrees [-90, 90]
-    ///   - longitude2: Second point longitude in degrees [-180, 180]
+    ///   - startLatitude: First point latitude in degrees [-90, 90]
+    ///   - startLongitude: First point longitude in degrees [-180, 180]
+    ///   - endLatitude: Second point latitude in degrees [-90, 90]
+    ///   - endLongitude: Second point longitude in degrees [-180, 180]
     ///   - capabilities: Capabilities for calculations
     /// - Returns: A geodesic line connecting the two points
-    func inverseLine(latitude1: Double, longitude1: Double, latitude2: Double, longitude2: Double,
-                     capabilities: GeodesicCapability = .standard) -> GeodesicLine {
+    func inverseLine(
+        startLatitude: Double,
+        startLongitude: Double,
+        endLatitude: Double,
+        endLongitude: Double,
+        capabilities: GeodesicCapability = .standard
+    ) -> GeodesicLine {
         var line = geod_geodesicline()
         withUnsafePointer(to: geod) { geodPtr in
-            geod_inverseline(&line, geodPtr, latitude1, longitude1, latitude2, longitude2, capabilities.rawValue)
+            geod_inverseline(&line, geodPtr, startLatitude, startLongitude, endLatitude, endLongitude, capabilities.rawValue)
         }
 
-        var result = GeodesicLine(geodesic: self, latitude: latitude1, longitude: longitude1,
+        var result = GeodesicLine(geodesic: self, latitude: startLatitude, longitude: startLongitude,
                                 azimuth: 0, capabilities: capabilities)
         result.line = line
         return result

Tests/GeographicLibTests/GeodesicLineTests.swift

@@ -57,22 +57,27 @@ struct GeodesicLineTests {
         let geodesic = Geodesic()
 
         // JFK to Singapore
-        let lat1 = 40.64
-        let lon1 = -73.78
-        let lat2 = 1.36
-        let lon2 = 103.99
+        let startLatitude = 40.64
+        let startLongitude = -73.78
+        let endLatitude = 1.36
+        let endLongitude = 103.99
 
-        let line = geodesic.inverseLine(latitude1: lat1, longitude1: lon1, latitude2: lat2, longitude2: lon2)
+        let line = geodesic.inverseLine(
+            startLatitude: startLatitude,
+            startLongitude: startLongitude,
+            endLatitude: endLatitude,
+            endLongitude: endLongitude
+        )
 
-        #expect(line.latitude == lat1)
-        #expect(line.longitude == lon1)
+        #expect(line.latitude == startLatitude)
+        #expect(line.longitude == startLongitude)
 
         // The line should connect the two points
         let inverseResult = geodesic.inverse(
-            startLatitude: lat1,
-            startLongitude: lon1,
-            endLatitude: lat2,
-            endLongitude: lon2
+            startLatitude: startLatitude,
+            startLongitude: startLongitude,
+            endLatitude: endLatitude,
+            endLongitude: endLongitude
         )
         #expect(abs(line.distance - inverseResult.distance) < 0.001)
         #expect(abs(line.azimuth - inverseResult.startAzimuth) < 1e-10)
@@ -84,8 +89,10 @@ struct GeodesicLineTests {
 
         // Create line from JFK to Singapore
         let line = geodesic.inverseLine(
-            latitude1: 40.64, longitude1: -73.78,
-            latitude2: 1.36, longitude2: 103.99
+            startLatitude: 40.64,
+            startLongitude: -73.78,
+            endLatitude: 1.36,
+            endLongitude: 103.99
         )
 
         // Generate 11 waypoints (0%, 10%, ..., 100%)