Merge pull request #24 from wingkwong/develop

0.5.0 Release
wingkwong · Jun 18, 2023 · f64ee53 · f64ee53
2 parents 07e3bfb + 3806a2f
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diff --git a/README.md b/README.md
@@ -9,7 +9,7 @@ A Dart library for implementing geodesic and trigonometric calculations based on
 ### Add the following line in your `pubspec.yml` file
 
 ```dart
-geodesy:
+geodesy:<latest_version>
 ```
 
 ### Include the widget in your dart file
@@ -132,3 +132,45 @@ final pointsToCheck = <LatLng>[/* points here */];
 final distance = 10000;
 List<LatLng> geoFencedPoints = geodesy.pointsInRange(point, pointsToCheck, distance);
 ```
+
+### getRectangleBounds(List<LatLng> polygonCoords)
+
+Similar to PolygonEnvelop in Python
+
+```dart
+  List<LatLng> polygonCoords = [
+    const LatLng(37.7749, -122.4194),
+    const LatLng(37.3382, -121.8863),
+    const LatLng(37.7749, -121.4194),
+    const LatLng(37.7749, -123.4194),
+  ];
+
+  List<LatLng> rectangleBounds = geodesy.getRectangleBounds(polygonCoords);
+```
+
+### Great-circle distance between two points using the Haversine formula
+
+Calculate the Great-Circle Distance between two Geo points
+
+```dart
+num latitude1 = 37.7749;
+  num longitude1 = -122.4194;
+  num latitude2 = 37.3382;
+  num longitude2 = -121.8863;
+
+  num greatCircleDistance = geodesy.greatCircleDistanceBetweenTwoGeoPoints(
+      latitude1, longitude1, latitude2, longitude2);
+```
+
+### calculateBoundingBox(LatLng centerPoint, num distanceInKm)
+
+Given the Latitude and Longitude and distance in kilometers it calculate the bounding box value
+
+```dart
+  final centerPoint = const LatLng(
+      37.7749, -122.4194); // Example central position (San Francisco)
+
+  final distanceInKm = 1.0; // Example distance in kilometers
+
+  final boundingBox = geodesy.calculateBoundingBox(centerPoint, distanceInKm);
+```
diff --git a/example/main.dart b/example/main.dart
@@ -12,12 +12,12 @@ void main() async {
   print('[distanceBetweenTwoGeoPoints] Distance: ' + distance.toString());
 
   var l3 = const LatLng(51.4778, -0.0015);
-  var distinationPoint =
+  var destinationPoint =
       geodesy.destinationPointByDistanceAndBearing(l3, 7794.0, 300.7);
   print('[destinationPointByDistanceAndBearing] Lat: ' +
-      distinationPoint.latitude.toString());
+      destinationPoint.latitude.toString());
   print('[destinationPointByDistanceAndBearing] Lng: ' +
-      distinationPoint.longitude.toString());
+      destinationPoint.longitude.toString());
 
   var l4 = const LatLng(52.205, 0.119);
   var l5 = const LatLng(48.857, 2.351);
@@ -57,4 +57,43 @@ void main() async {
   var l7 = const LatLng(1.5, 1.5);
   var isGeoPointInPolygon = geodesy.isGeoPointInPolygon(l7, poly);
   print('[isGeoPointInPolygon] :' + isGeoPointInPolygon.toString());
+
+  // Great-circle distance between two points using the Haversine formula
+  num latitude1 = 37.7749;
+  num longitude1 = -122.4194;
+  num latitude2 = 37.3382;
+  num longitude2 = -121.8863;
+
+  num greatCircleDistance = geodesy.greatCircleDistanceBetweenTwoGeoPoints(
+      latitude1, longitude1, latitude2, longitude2);
+
+  print(
+      '''[greatCircleDistance]: ${greatCircleDistance.toStringAsFixed(2)} km''');
+
+  // Polygon Coords
+  List<LatLng> polygonCoords = [
+    const LatLng(37.7749, -122.4194),
+    const LatLng(37.3382, -121.8863),
+    const LatLng(37.7749, -121.4194),
+    const LatLng(37.7749, -123.4194),
+  ];
+
+  List<LatLng> rectangleBounds = geodesy.getRectangleBounds(polygonCoords);
+
+  print('[getRectangleBounds]: ');
+  for (LatLng coord in rectangleBounds) {
+    print(' > Latitude: ${coord.latitude}, Longitude: ${coord.longitude}');
+  }
+
+  // Calculate Bounding Box
+  // Example central position (San Francisco)
+  final centerPoint = const LatLng(37.7749, -122.4194);
+  // Example distance in kilometers
+  final distanceInKm = 1.0;
+
+  final boundingBox = geodesy.calculateBoundingBox(centerPoint, distanceInKm);
+
+  print('[calculateBoundingBox]: ');
+  print(' > Top Left: ${boundingBox[0]}');
+  print(' > Bottom Right: ${boundingBox[1]}');
 }
diff --git a/lib/src/geodesy.dart b/lib/src/geodesy.dart
@@ -229,4 +229,75 @@ class Geodesy {
     }
     return geoFencedPoints;
   }
+
+  /// great-circle distance between two points using the Haversine formula
+  num greatCircleDistanceBetweenTwoGeoPoints(
+      num lat1, num lon1, num lat2, num lon2) {
+    final num earthRadius = _RADIUS; // Radius of the earth in kilometers
+
+    num dLat = degToRadian(lat2.toDouble() - lat1.toDouble());
+    num dLon = degToRadian(lon2.toDouble() - lon1.toDouble());
+
+    num a = math.sin(dLat / 2) * math.sin(dLat / 2) +
+        math.cos(degToRadian(lat1.toDouble())) *
+            math.cos(degToRadian(lat2.toDouble())) *
+            math.sin(dLon / 2) *
+            math.sin(dLon / 2);
+    num c = 2 * math.atan2(math.sqrt(a), math.sqrt(1 - a));
+    num distance = earthRadius * c;
+
+    return distance;
+  }
+
+  /// GetRectangleBounds
+
+  List<LatLng> getRectangleBounds(List<LatLng> polygonCoords) {
+    num minLatitude = double.infinity.toDouble();
+    num maxLatitude = double.negativeInfinity.toDouble();
+    num minLongitude = double.infinity.toDouble();
+    num maxLongitude = double.negativeInfinity.toDouble();
+
+    for (LatLng coord in polygonCoords) {
+      if (coord.latitude < minLatitude) {
+        minLatitude = coord.latitude;
+      }
+      if (coord.latitude > maxLatitude) {
+        maxLatitude = coord.latitude;
+      }
+      if (coord.longitude < minLongitude) {
+        minLongitude = coord.longitude;
+      }
+      if (coord.longitude > maxLongitude) {
+        maxLongitude = coord.longitude;
+      }
+    }
+
+    List<LatLng> rectangleBounds = [
+      LatLng(minLatitude.toDouble(), minLongitude.toDouble()),
+      LatLng(minLatitude.toDouble(), maxLongitude.toDouble()),
+      LatLng(maxLatitude.toDouble(), maxLongitude.toDouble()),
+      LatLng(maxLatitude.toDouble(), minLongitude.toDouble()),
+    ];
+
+    return rectangleBounds;
+  }
+
+  /// Bounding Box per distance in Kilometers
+  List<LatLng> calculateBoundingBox(LatLng centerPoint, num distanceInKm) {
+    // Earth's radius in kilometers
+    final num radiusOfEarth = _RADIUS / 1000;
+    // Convert latitude to radians
+    final num latInRadians = centerPoint.latitude * (_PI / 180.0);
+    final num degreeLatDistance =
+        (distanceInKm / radiusOfEarth) * (180.0 / _PI);
+    final num degreeLngDistance = degreeLatDistance / math.cos(latInRadians);
+    final num topLat = centerPoint.latitude + degreeLatDistance;
+    final num leftLng = centerPoint.longitude - degreeLngDistance;
+    final num bottomLat = centerPoint.latitude - degreeLatDistance;
+    final num rightLng = centerPoint.longitude + degreeLngDistance;
+    final LatLng topLeft = LatLng(topLat.toDouble(), leftLng.toDouble());
+    final LatLng bottomRight =
+        LatLng(bottomLat.toDouble(), rightLng.toDouble());
+    return [topLeft, bottomRight];
+  }
 }
diff --git a/test/geodesy_test.dart b/test/geodesy_test.dart
@@ -98,4 +98,70 @@ void main() {
     expect((geoFencedPoints.contains(pointInRange)), true);
     expect((geoFencedPoints.contains(pointNotInRange)), false);
   });
+
+  test('Great-Circle distance between two points using the Haversine formula',
+      () async {
+    const num latitude1 = 52.5200; // Latitude of the first point
+    const num longitude1 = 13.4050; // Longitude of the first point
+    const num latitude2 = 48.8566; // Latitude of the second point
+    const num longitude2 = 2.3522; // Longitude of the second point
+
+    const num expectedDistance = 877460.0; // Expected distance in kilometers
+
+    final num distance = geodesy.greatCircleDistanceBetweenTwoGeoPoints(
+        latitude1, longitude1, latitude2, longitude2);
+
+    expect(distance, closeTo(expectedDistance, 10.0));
+  });
+
+  test('getRectangleBounds returns correct rectangle bounds', () async {
+    List<LatLng> polygonCoords = [
+      const LatLng(37.7749, -122.4194),
+      const LatLng(37.3382, -121.8863),
+      const LatLng(37.7749, -121.4194),
+      const LatLng(37.7749, -123.4194),
+    ];
+
+    List<LatLng> expectedRectangleBounds = [
+      const LatLng(37.3382, -123.4194),
+      const LatLng(37.3382, -121.4194),
+      const LatLng(37.7749, -121.4194),
+      const LatLng(37.7749, -123.4194),
+    ];
+
+    List<LatLng> rectangleBounds = geodesy.getRectangleBounds(polygonCoords);
+
+    // Assert that the rectangle bounds are calculated correctly
+    expect(rectangleBounds.length, expectedRectangleBounds.length);
+    for (int i = 0; i < expectedRectangleBounds.length; i++) {
+      LatLng expectedCoord = expectedRectangleBounds[i];
+      LatLng actualCoord = rectangleBounds[i];
+      expect(actualCoord.latitude, expectedCoord.latitude);
+      expect(actualCoord.longitude, expectedCoord.longitude);
+    }
+  });
+
+  group('calculateBoundingBox', () {
+    test(
+        '''should calculate the correct bounding box for a given center point and distance''',
+        () async {
+      final centerPoint = const LatLng(40.0, -73.0); // Example center point
+      final distanceInKm = 10.0; // Example distance in kilometers
+
+      final result = geodesy.calculateBoundingBox(centerPoint, distanceInKm);
+
+      // Expected coordinates for the bounding box
+      final expectedTopLeft =
+          const LatLng(40.09090909090909, -73.16323914050199);
+      final expectedBottomRight =
+          const LatLng(39.90909090909091, -72.836760859498);
+
+      // Check if the calculated bounding box matches the expected coordinates
+      expect(result[0].latitude, closeTo(expectedTopLeft.latitude, 0.1));
+      expect(result[0].longitude, closeTo(expectedTopLeft.longitude, 0.1));
+      expect(result[1].latitude, closeTo(expectedBottomRight.latitude, 0.1));
+      expect(result[1].longitude, closeTo(expectedBottomRight.longitude, 0.1));
+    });
+  });
+
 }