diff --git a/MapControl/Shared/LocationCollection.cs b/MapControl/Shared/LocationCollection.cs
index eda679f4..52733042 100644
--- a/MapControl/Shared/LocationCollection.cs
+++ b/MapControl/Shared/LocationCollection.cs
@@ -9,7 +9,7 @@ using System.Linq;
namespace MapControl
{
///
- /// A collection of Locations with support for parsing.
+ /// A collection of Locations with support for string parsing and calculation of great circle and rhumb line locations.
///
#if !WINDOWS_UWP
[System.ComponentModel.TypeConverter(typeof(LocationCollectionConverter))]
@@ -30,11 +30,155 @@ namespace MapControl
{
}
+ public void Add(double latitude, double longitude)
+ {
+ if (Count > 0)
+ {
+ var deltaLon = longitude - this[Count - 1].Longitude;
+
+ if (deltaLon < -180d)
+ {
+ longitude += 360d;
+ }
+ else if (deltaLon > 180)
+ {
+ longitude -= 360;
+ }
+ }
+
+ Add(new Location(latitude, longitude));
+ }
+
public static LocationCollection Parse(string s)
{
var strings = s.Split(new char[] { ' ', ';' }, StringSplitOptions.RemoveEmptyEntries);
return new LocationCollection(strings.Select(l => Location.Parse(l)));
}
+
+ ///
+ /// see https://en.wikipedia.org/wiki/Great-circle_navigation
+ ///
+ public static LocationCollection CalculateGreatCircleLocations(Location location1, Location location2, double resolution = 1d)
+ {
+ if (resolution <= 0d)
+ {
+ throw new ArgumentOutOfRangeException(
+ nameof(resolution), "The parameter resolution must be greater than zero.");
+ }
+
+ resolution *= Math.PI / 180d;
+
+ var lat1 = location1.Latitude * Math.PI / 180d;
+ var lon1 = location1.Longitude * Math.PI / 180d;
+ var lat2 = location2.Latitude * Math.PI / 180d;
+ var lon2 = location2.Longitude * Math.PI / 180d;
+ var cosLat1 = Math.Cos(lat1);
+ var sinLat1 = Math.Sin(lat1);
+ var cosLat2 = Math.Cos(lat2);
+ var sinLat2 = Math.Sin(lat2);
+ var cosLon12 = Math.Cos(lon2 - lon1);
+ var sinLon12 = Math.Sin(lon2 - lon1);
+
+ var a = cosLat1 * sinLat2 - sinLat1 * cosLat2 * cosLon12;
+ var b = cosLat2 * sinLon12;
+ var s12 = Math.Atan2(Math.Sqrt(a * a + b * b), sinLat1 * sinLat2 + cosLat1 * cosLat2 * cosLon12);
+
+ var locations = new LocationCollection(new Location(location1.Latitude, location1.Longitude));
+
+ if (s12 > resolution)
+ {
+ var n = (int)Math.Round(s12 / resolution);
+
+ var az1 = Math.Atan2(sinLon12, cosLat1 * sinLat2 / cosLat2 - sinLat1 * cosLon12);
+ var cosAz1 = Math.Cos(az1);
+ var sinAz1 = Math.Sin(az1);
+
+ var az0 = Math.Atan2(sinAz1 * cosLat1, Math.Sqrt(cosAz1 * cosAz1 + sinAz1 * sinAz1 * sinLat1 * sinLat1));
+ var sinAz0 = Math.Sin(az0);
+ var cosAz0 = Math.Cos(az0);
+
+ var s01 = Math.Atan2(sinLat1, cosLat1 * cosAz1);
+ var lon0 = lon1 - Math.Atan2(sinAz0 * Math.Sin(s01), Math.Cos(s01));
+
+ for (int i = 1; i < n; i++)
+ {
+ double s = s01 + i * s12 / n;
+ double sinS = Math.Sin(s);
+ double cosS = Math.Cos(s);
+ double lat = Math.Atan2(cosAz0 * sinS, Math.Sqrt(cosS * cosS + sinAz0 * sinAz0 * sinS * sinS));
+ double lon = Math.Atan2(sinAz0 * sinS, cosS) + lon0;
+
+ locations.Add(lat * 180d / Math.PI, lon * 180d / Math.PI);
+ }
+ }
+
+ locations.Add(location2.Latitude, location2.Longitude);
+
+ return locations;
+ }
+
+ ///
+ /// see https://en.wikipedia.org/wiki/Rhumb_line
+ ///
+ public static LocationCollection CalculateRhumbLineLocations(Location location1, Location location2, double resolution = 1d)
+ {
+ if (resolution <= 0d)
+ {
+ throw new ArgumentOutOfRangeException(
+ nameof(resolution), "The parameter resolution must be greater than zero.");
+ }
+
+ resolution *= Math.PI / 180d;
+
+ var lat1 = location1.Latitude;
+ var lat2 = location2.Latitude;
+ var y1 = WebMercatorProjection.LatitudeToY(lat1);
+ var y2 = WebMercatorProjection.LatitudeToY(lat2);
+
+ if (double.IsInfinity(y1))
+ {
+ throw new ArgumentOutOfRangeException(
+ nameof(location1), "The parameter location1 must have an absolute latitude value of less than 90 degrees.");
+ }
+
+ if (double.IsInfinity(y2))
+ {
+ throw new ArgumentOutOfRangeException(
+ nameof(location2), "The parameter location2 must have an absolute latitude value of less than 90 degrees.");
+ }
+
+ var lon1 = location1.Longitude;
+ var lon2 = location2.Longitude;
+ var dlat = lat2 - lat1;
+ var dlon = lon2 - lon1;
+ var dy = y2 - y1;
+
+ // sec(beta) = 1 / cos(atan(dx,dy)) = sqrt(1 + (dx/dy)^2)
+ var sec = Math.Sqrt(1d + dlon * dlon / (dy * dy));
+
+ var s12 = sec < 1000d
+ ? Math.Abs(dlat * Math.PI / 180d * sec)
+ : Math.Abs(dlon * Math.PI / 180d);
+
+ var locations = new LocationCollection(new Location(lat1, lon1));
+
+ if (s12 > resolution)
+ {
+ var n = (int)Math.Round(s12 / resolution);
+
+ for (int i = 1; i < n; i++)
+ {
+ double lon = lon1 + i * dlon / n;
+ double lat = WebMercatorProjection.YToLatitude(y1 + i * dy / n);
+
+ locations.Add(lat, lon);
+ }
+ }
+
+ locations.Add(lat2, lon2);
+
+ return locations;
+ }
}
}
diff --git a/MapControl/Shared/LocationEx.cs b/MapControl/Shared/LocationEx.cs
index c40e4515..57e35352 100644
--- a/MapControl/Shared/LocationEx.cs
+++ b/MapControl/Shared/LocationEx.cs
@@ -3,7 +3,6 @@
// Licensed under the Microsoft Public License (Ms-PL)
using System;
-using System.Linq;
namespace MapControl
{
@@ -15,7 +14,8 @@ namespace MapControl
///
/// see https://en.wikipedia.org/wiki/Great-circle_navigation
///
- public static double GreatCircleDistance(this Location location1, Location location2, double earthRadius = MapProjection.Wgs84EquatorialRadius)
+ public static double GreatCircleDistance(
+ this Location location1, Location location2, double earthRadius = MapProjection.Wgs84EquatorialRadius)
{
var lat1 = location1.Latitude * Math.PI / 180d;
var lon1 = location1.Longitude * Math.PI / 180d;
@@ -37,7 +37,8 @@ namespace MapControl
///
/// see https://en.wikipedia.org/wiki/Great-circle_navigation
///
- public static Location GreatCircleLocation(this Location location, double azimuth, double distance, double earthRadius = MapProjection.Wgs84EquatorialRadius)
+ public static Location GreatCircleLocation(
+ this Location location, double azimuth, double distance, double earthRadius = MapProjection.Wgs84EquatorialRadius)
{
var s12 = distance / earthRadius;
var az1 = azimuth * Math.PI / 180d;
@@ -54,151 +55,5 @@ namespace MapControl
return new Location(lat2 * 180d / Math.PI, lon2 * 180d / Math.PI);
}
-
- public static LocationCollection CalculateMeridianLocations(this Location location, double latitude2, double resolution = 1d)
- {
- if (resolution <= 0d)
- {
- throw new ArgumentOutOfRangeException("The parameter resolution must be greater than zero.");
- }
-
- var locations = new LocationCollection();
- var s = latitude2 - location.Latitude;
- var n = (int)Math.Ceiling(Math.Abs(s) / resolution);
-
- for (int i = 0; i <= n; i++)
- {
- locations.Add(new Location(location.Latitude + i * s / n, location.Longitude));
- }
-
- return locations;
- }
-
- ///
- /// see https://en.wikipedia.org/wiki/Great-circle_navigation
- ///
- public static LocationCollection CalculateGreatCircleLocations(this Location location1, Location location2, double resolution = 1d)
- {
- if (resolution <= 0d)
- {
- throw new ArgumentOutOfRangeException("The parameter resolution must be greater than zero.");
- }
-
- if (location1.Longitude == location2.Longitude ||
- location1.Latitude <= -90d || location1.Latitude >= 90d ||
- location2.Latitude <= -90d || location2.Latitude >= 90d)
- {
- return CalculateMeridianLocations(location1, location2.Latitude);
- }
-
- var locations = new LocationCollection(new Location(location1.Latitude, location1.Longitude));
-
- var lat1 = location1.Latitude * Math.PI / 180d;
- var lon1 = location1.Longitude * Math.PI / 180d;
- var lat2 = location2.Latitude * Math.PI / 180d;
- var lon2 = location2.Longitude * Math.PI / 180d;
- var cosLat1 = Math.Cos(lat1);
- var sinLat1 = Math.Sin(lat1);
- var cosLat2 = Math.Cos(lat2);
- var sinLat2 = Math.Sin(lat2);
- var cosLon12 = Math.Cos(lon2 - lon1);
- var sinLon12 = Math.Sin(lon2 - lon1);
-
- var cosS12 = sinLat1 * sinLat2 + cosLat1 * cosLat2 * cosLon12;
- var s12 = Math.Acos(Math.Min(Math.Max(cosS12, -1d), 1d));
- var n = (int)Math.Ceiling(s12 / resolution * 180d / Math.PI);
-
- if (n > 1)
- {
- var az1 = Math.Atan2(sinLon12, cosLat1 * sinLat2 / cosLat2 - sinLat1 * cosLon12);
- var cosAz1 = Math.Cos(az1);
- var sinAz1 = Math.Sin(az1);
-
- var az0 = Math.Atan2(sinAz1 * cosLat1, Math.Sqrt(cosAz1 * cosAz1 + sinAz1 * sinAz1 * sinLat1 * sinLat1));
- var sinAz0 = Math.Sin(az0);
- var cosAz0 = Math.Cos(az0);
-
- var s01 = Math.Atan2(sinLat1, cosLat1 * cosAz1);
- var lon0 = lon1 - Math.Atan2(sinAz0 * Math.Sin(s01), Math.Cos(s01));
-
- for (int i = 1; i < n; i++)
- {
- double s = s01 + i * s12 / n;
- double sinS = Math.Sin(s);
- double cosS = Math.Cos(s);
- double lat = Math.Atan2(cosAz0 * sinS, Math.Sqrt(cosS * cosS + sinAz0 * sinAz0 * sinS * sinS));
- double lon = Math.Atan2(sinAz0 * sinS, cosS) + lon0;
-
- locations.Add(lat * 180d / Math.PI, lon * 180d / Math.PI);
- }
- }
-
- locations.Add(location2.Latitude, location2.Longitude);
- return locations;
- }
-
- ///
- /// see https://en.wikipedia.org/wiki/Rhumb_line
- ///
- public static LocationCollection CalculateRhumbLineLocations(this Location location1, Location location2, double resolution = 1d)
- {
- if (resolution <= 0d)
- {
- throw new ArgumentOutOfRangeException("The parameter resolution must be greater than zero.");
- }
-
- var y1 = WebMercatorProjection.LatitudeToY(location1.Latitude);
-
- if (double.IsInfinity(y1))
- {
- throw new ArgumentOutOfRangeException("The parameter location1 must have an absolute latitude value of less than 90 degrees.");
- }
-
- var y2 = WebMercatorProjection.LatitudeToY(location2.Latitude);
-
- if (double.IsInfinity(y2))
- {
- throw new ArgumentOutOfRangeException("The parameter location2 must have an absolute latitude value of less than 90 degrees.");
- }
-
- var x1 = location1.Longitude;
- var x2 = location2.Longitude;
- var dx = x2 - x1;
- var dy = y2 - y1;
- var s = Math.Sqrt(dx * dx + dy * dy);
- var n = (int)Math.Ceiling(s / resolution);
-
- var locations = new LocationCollection(new Location(location1.Latitude, location1.Longitude));
-
- for (int i = 1; i < n; i++)
- {
- double x = x1 + i * dx / n;
- double y = y1 + i * dy / n;
-
- locations.Add(WebMercatorProjection.YToLatitude(y), x);
- }
-
- locations.Add(location2.Latitude, location2.Longitude);
- return locations;
- }
-
- public static void Add(this LocationCollection locations, double latitude, double longitude)
- {
- if (locations.Count > 0)
- {
- var deltaLon = longitude - locations.Last().Longitude;
-
- if (deltaLon < -180d)
- {
- longitude += 360d;
- }
- else if (deltaLon > 180)
- {
- longitude -= 360;
- }
- }
-
- locations.Add(new Location(latitude, longitude));
- }
}
}