XAML-Map-Control/MapProjections/Shared/Wgs84OrthographicProjection.cs
2026-01-20 15:48:30 +01:00

48 lines
1.6 KiB
C#

using System;
using System.Globalization;
#if WPF
using System.Windows.Media;
#endif
namespace MapControl.Projections
{
/// <summary>
/// Spherical Orthographic Projection - AUTO2:42003.
/// See "Map Projections - A Working Manual" (https://pubs.usgs.gov/publication/pp1395), p.148-150.
/// </summary>
public class Wgs84OrthographicProjection : ProjNetMapProjection
{
public Wgs84OrthographicProjection()
{
CenterChanged();
}
protected override void CenterChanged()
{
var wktFormat =
"PROJCS[\"WGS 84 / World Mercator\"," +
WktConstants.GeogCsWgs84 + "," +
"PROJECTION[\"Orthographic\"]," +
"PARAMETER[\"latitude_of_origin\",{0:0.########}]," +
"PARAMETER[\"central_meridian\",{1:0.########}]," +
"UNIT[\"metre\",1,AUTHORITY[\"EPSG\",\"9001\"]]," +
"AXIS[\"Easting\",EAST]," +
"AXIS[\"Northing\",NORTH]" +
"AUTHORITY[\"AUTO2\",\"42003\"]]";
CoordinateSystemWkt = string.Format(
CultureInfo.InvariantCulture, wktFormat, Center.Latitude, Center.Longitude);
}
public override Matrix RelativeScale(double latitude, double longitude)
{
var p = new AzimuthalProjection.ProjectedPoint(Center.Latitude, Center.Longitude, latitude, longitude);
var h = p.CosC; // p.149 (20-5)
var scale = new Matrix(h, 0d, 0d, 1d, 0d, 0d);
scale.Rotate(-Math.Atan2(p.Y, p.X) * 180d / Math.PI);
return scale;
}
}
}