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Updated PolarStereographicProjection

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ClemensFischer 2026-01-18 21:03:25 +01:00
parent 31b38d5049
commit 19cba8978b
3 changed files with 13 additions and 19 deletions
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12
MapControl/Shared/PolarStereographicProjection.cs
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@ -26,7 +26,7 @@ namespace MapControl
public double FalseNorthing { get; set; } = 2e6;
public Hemisphere Hemisphere { get; set; }
public static double RelativeScale(Hemisphere hemisphere, double equatorialRadius, double flattening, double scaleFactor, double latitude)
public static double RelativeScale(Hemisphere hemisphere, double flattening, double scaleFactor, double latitude)
{
var sign = hemisphere == Hemisphere.North ? 1d : -1d;
var phi = sign * latitude * Math.PI / 180d;
@ -36,17 +36,19 @@ namespace MapControl
var t = Math.Tan(Math.PI / 4d - phi / 2d)
/ Math.Pow((1d - eSinPhi) / (1d + eSinPhi), e / 2d); // p.161 (15-9)
var r = 2d * equatorialRadius * scaleFactor * t
// r == ρ/a
var r = 2d * scaleFactor * t
/ Math.Sqrt(Math.Pow(1d + e, 1d + e) * Math.Pow(1d - e, 1d - e)); // p.161 (21-33)
var m = Math.Cos(phi) / Math.Sqrt(1d - eSinPhi * eSinPhi); // p.160 (14-15)
return r / (equatorialRadius * m); // p.161 (21-32)
return r / m; // p.161 (21-32)
}
public override Point RelativeScale(double latitude, double longitude)
{
var k = RelativeScale(Hemisphere, EquatorialRadius, Flattening, ScaleFactor, latitude);
var k = RelativeScale(Hemisphere, Flattening, ScaleFactor, latitude);
return new Point(k, k);
}
@ -62,7 +64,7 @@ namespace MapControl
var t = Math.Tan(Math.PI / 4d - phi / 2d)
/ Math.Pow((1d - eSinPhi) / (1d + eSinPhi), e / 2d); // p.161 (15-9)
// ρ
var r = 2d * EquatorialRadius * ScaleFactor * t
/ Math.Sqrt(Math.Pow(1d + e, 1d + e) * Math.Pow(1d - e, 1d - e)); // p.161 (21-33)