mirror of
https://github.com/ClemensFischer/XAML-Map-Control.git
synced 2025-12-06 07:12:04 +01:00
49 lines
2 KiB
C#
49 lines
2 KiB
C#
// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
|
|
// © 2018 Clemens Fischer
|
|
// Licensed under the Microsoft Public License (Ms-PL)
|
|
|
|
using System;
|
|
#if !WINDOWS_UWP
|
|
using System.Windows;
|
|
#endif
|
|
|
|
namespace MapControl.Projections
|
|
{
|
|
/// <summary>
|
|
/// Elliptical Mercator Projection implemented by setting the WKT property of a GeoApiProjection.
|
|
/// See "Map Projections - A Working Manual" (https://pubs.usgs.gov/pp/1395/report.pdf), p.44-45.
|
|
/// </summary>
|
|
public class WorldMercatorProjection : GeoApiProjection
|
|
{
|
|
public WorldMercatorProjection()
|
|
{
|
|
IsNormalCylindrical = true;
|
|
WKT = "PROJCS[\"WGS 84 / World Mercator\","
|
|
+ "GEOGCS[\"WGS 84\","
|
|
+ "DATUM[\"WGS_1984\", SPHEROID[\"WGS 84\", 6378137, 298.257223563, AUTHORITY[\"EPSG\", \"7030\"]], AUTHORITY[\"EPSG\", \"6326\"]],"
|
|
+ "PRIMEM[\"Greenwich\", 0, AUTHORITY[\"EPSG\", \"8901\"]],"
|
|
+ "UNIT[\"degree\", 0.0174532925199433, AUTHORITY[\"EPSG\", \"9122\"]],"
|
|
+ "AUTHORITY[\"EPSG\", \"4326\"]],"
|
|
+ "PROJECTION[\"Mercator_1SP\"],"
|
|
+ "PARAMETER[\"latitude_of_origin\", 0],"
|
|
+ "PARAMETER[\"central_meridian\", 0],"
|
|
+ "PARAMETER[\"scale_factor\", 1],"
|
|
+ "PARAMETER[\"false_easting\", 0],"
|
|
+ "PARAMETER[\"false_northing\", 0],"
|
|
+ "UNIT[\"metre\", 1, AUTHORITY[\"EPSG\", \"9001\"]],"
|
|
+ "AXIS[\"Easting\", EAST],"
|
|
+ "AXIS[\"Northing\", NORTH],"
|
|
+ "AUTHORITY[\"EPSG\", \"3395\"]]";
|
|
}
|
|
|
|
public override Vector GetMapScale(Location location)
|
|
{
|
|
var lat = location.Latitude * Math.PI / 180d;
|
|
var eSinLat = Wgs84Eccentricity * Math.Sin(lat);
|
|
var k = Math.Sqrt(1d - eSinLat * eSinLat) / Math.Cos(lat); // p.44 (7-8)
|
|
|
|
return new Vector(ViewportScale * k, ViewportScale * k);
|
|
}
|
|
}
|
|
}
|