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MapProjection.RelativeTransform

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ClemensFischer 2026-01-27 22:56:09 +01:00
parent a0e82964ef
commit 8d25310b8e
19 changed files with 59 additions and 50 deletions
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20
MapControl/Shared/TransverseMercatorProjectionSnyder.cs
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@ -45,23 +45,26 @@ namespace MapControl
e6 * 35d / 3072d * Math.Sin(6d * phi)); // (3-21)
}
public override Matrix RelativeScale(double latitude, double longitude)
public override Matrix RelativeTransform(double latitude, double longitude)
{
// h = k/k0 for relative scale
var h = 1d;
// γ, meridian convergence angle
var gamma = 0d;
#if TM_RELATIVE_SCALE // relative scale is usually < 1.001 and hence neglectable
if (latitude > -90d && latitude < 90d)
{
var phi = latitude * Math.PI / 180d;
var sinPhi = Math.Sin(phi);
var cosPhi = Math.Cos(phi);
var tanPhi = Math.Tan(phi);
var tanPhi = sinPhi / cosPhi;
var dLambda = (longitude - CentralMeridian) * Math.PI / 180d;
var e2 = (2d - Flattening) * Flattening;
var e_2 = e2 / (1d - e2); // (8-12)
var T = tanPhi * tanPhi; // (8-13)
var C = e_2 * cosPhi * cosPhi; // (8-14)
var A = (longitude - CentralMeridian) * Math.PI / 180d * cosPhi; // (8-15)
var A = dLambda * cosPhi; // (8-15)
var A2 = A * A;
var A4 = A2 * A2;
var A6 = A2 * A4;
@ -69,9 +72,14 @@ namespace MapControl
h = 1d + (1d + C) * A2 / 2d +
(5d - 4d * T + 42d * C + 13d * C * C - 28d * e_2) * A4 / 24d +
(61d - 148d * T + 16 * T * T) * A6 / 720d; // (8-11)
gamma = Math.Atan(Math.Tan(dLambda) * sinPhi);
}
#endif
return new Matrix(h, 0d, 0d, h, 0d, 0d);
var transform = new Matrix(h, 0d, 0d, h, 0d, 0d);
transform.Rotate(-gamma * 180d / Math.PI);
return transform;
}
public override Point? LocationToMap(double latitude, double longitude)