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desruisseaux pushed a commit to branch geoapi-4.0
in repository https://gitbox.apache.org/repos/asf/sis.git
commit 8c2d72d85ff84114983ef2e1f62cd2cf5e538585
Author: Matthieu_Bastianelli <matthieu.bastiane...@geomatys.com>
AuthorDate: Thu Jul 25 12:18:37 2019 +0200
refactor (referencing satellite-tracking projections) : Method used by both
(cylindrical and conic) direct transformation of the Satellite-tracking
projections to compute the L coefficient and its partial derivate dL_dφ if
queried. Test passed for both transformation and testDerivativeOnSphere.
---
.../projection/ConicSatelliteTracking.java | 61 ++++++++++++++++------
.../projection/CylindricalSatelliteTracking.java | 17 +++---
2 files changed, 50 insertions(+), 28 deletions(-)
diff --git
a/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/projection/ConicSatelliteTracking.java
b/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/projection/ConicSatelliteTracking.java
index 9b0b0b0..d265ae2 100644
---
a/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/projection/ConicSatelliteTracking.java
+++
b/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/projection/ConicSatelliteTracking.java
@@ -285,13 +285,9 @@ public class ConicSatelliteTracking extends
NormalizedProjection{
throw new
ProjectionException(Resources.format(Resources.Keys.CanNotTransformCoordinates_2));
}
- final double sin_φ = sin(φ);
- final double sinφ_sini = sin_φ / sin_i;
- final double dλ = -asin(sinφ_sini);
- final double tan_dλ = tan(dλ);
- final double λt = atan(tan_dλ * cos_i);
- final double L = λt - p2_on_p1 * dλ;
-
+ // compute an double array with {L} or {L, dL/dφ} if derivate
recquired.
+ final double[] vector_L = computeLanddLdφForDirectTransform(φ,
derivate);
+ final double L = vector_L[0];
/*
* As {@code latitudeLimit} is an approximation we repeat the test
here.
*/
@@ -301,17 +297,15 @@ public class ConicSatelliteTracking extends
NormalizedProjection{
throw new
ProjectionException(Resources.format(Resources.Keys.CanNotTransformCoordinates_2));
}
- final double nLandS0 = n*L+s0;
+ final double nLandS0 = n*L+s0;
final double sin_nLandS0 = sin(nLandS0);
-
- final double ρ = cosφ1xsinF1_n/sin_nLandS0;
-// final double ρ = 1/sin(n*L+s0);
+ final double ρ = cosφ1xsinF1_n/sin_nLandS0;
final double sinλ = sin(λ);
final double cosλ = cos(λ);
if (dstPts != null) {
- dstPts[dstOff ] = ρ * sinλ; // x
- dstPts[dstOff + 1] = - ρ*cosλ; // y
+ dstPts[dstOff ] = ρ * sinλ; // x
+ dstPts[dstOff + 1] = - ρ * cosλ; // y
}
if (!derivate) {
@@ -320,14 +314,12 @@ public class ConicSatelliteTracking extends
NormalizedProjection{
//=========================To check the resolution
=====================
final double dρ_dφ = cosφ1xsinF1_n * (-1 / (sin_nLandS0*sin_nLandS0))
*cos(nLandS0) * n
- // dL/dφ :
- * ((cos(φ) / sin_i) *(1/sqrt(1-sinφ_sini*sinφ_sini))) //
derivative of (-dλ/dφ)
- * ( p2_on_p1 - ((1+tan_dλ*tan_dλ)*cos_i/(1+λt*λt) ) );
+ * vector_L[1]; // dL/dφ
final double dx_dλ = ρ*cosλ;
final double dx_dφ = sinλ * dρ_dφ;
- final double dy_dλ = ρ*sinλ;
+ final double dy_dλ = ρ*sinλ;
final double dy_dφ = -cosλ * dρ_dφ;
//======================================================================
@@ -445,4 +437,39 @@ public class ConicSatelliteTracking extends
NormalizedProjection{
return atan(tan(dλn) * cos_i); // eq.28-3a in Snyder
}
+ /**
+ * Method returning the L coefficient used for the direct transformation of
+ * the Satellite-tracking projections and its partial derivate dL_dφ if
+ * queried by a true value of the input parameter derivate.
+ *
+ * This method is used By :
+ * {@link ConicSatelliteTracking#transform(double[], int, double[],
int, boolean) }
+ * and {@link CylindricalSatelliteTracking#transform(double[], int,
double[], int, boolean) }
+ *
+ * @param φ : input latitude of the projection's (direct) method.
+ * @param derivate : boolean value indicating if the partial derivate dL_dφ
+ * must be computed.
+ * @return a double array. It contains :
+ * - if derivate is false : only the L coefficient value.
+ * - if derivate is true : the L coefficient value and the partial
+ * derivate dL_dφ respectively at the at index 0 and 1 of the
+ * resulting array.
+ */
+ double[] computeLanddLdφForDirectTransform(final double φ, final boolean
derivate){
+
+ final double sinφ_sini = sin(φ) / sin_i;
+ final double dλ = -asin(sinφ_sini);
+ final double tan_dλ = tan(dλ);
+ final double λt = atan(tan_dλ * cos_i);
+ final double L = λt - p2_on_p1 * dλ;
+
+ if (derivate){
+ final double dL_dφ = ((cos(φ) / sin_i)
*(1/sqrt(1-sinφ_sini*sinφ_sini))) // first computed term associated with
derivative of (-dλ/dφ)
+ * ( p2_on_p1 -
((1+tan_dλ*tan_dλ)*cos_i/(1+λt*λt) ) );
+ return new double[] {L, dL_dφ};
+ } else {
+ return new double[] {L};
+ }
+ }
+
}
diff --git
a/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/projection/CylindricalSatelliteTracking.java
b/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/projection/CylindricalSatelliteTracking.java
index 9348834..4348993 100644
---
a/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/projection/CylindricalSatelliteTracking.java
+++
b/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/projection/CylindricalSatelliteTracking.java
@@ -127,21 +127,17 @@ public class CylindricalSatelliteTracking extends
ConicSatelliteTracking {
final double φ = srcPts[srcOff + 1];
// TODO : check the condition and the thrown exception.
- if (abs(φ) > PI / 2 - abs(PI / 2 - i)) { // Exceed tracking limit
+ // if (abs(φ) > PI / 2 - abs(PI - i)) { // Exceed tracking limit
+ if (φ > PI - i) { // Exceed tracking limit
throw new
ProjectionException(Resources.format(Resources.Keys.CanNotTransformCoordinates_2));
}
- final double sin_φ = sin(φ);
- final double sinφ_sini = sin_φ / sin_i;
-
- final double dλ = -asin(sin_φ / sin_i);
- final double tan_dλ = tan(dλ);
- final double λt = atan(tan(dλ) * cos_i);
- final double L = λt - p2_on_p1 * dλ;
+ // compute an double array with {L} or {L, dL/dφ} if derivate
recquired.
+ final double[] vector_L = computeLanddLdφForDirectTransform(φ,
derivate);
if (dstPts != null) {
dstPts[dstOff ] = λ; // In eq. Snyder 28-5 : R(λ - λ0) cos_φ1
- dstPts[dstOff + 1] = L; // In eq. Snyder 28-6 : R L cos(φ1)/F'1
+ dstPts[dstOff + 1] = vector_L[0]; // In eq. Snyder 28-6 : R L
cos(φ1)/F'1
}
/*
=====================================================================
@@ -162,8 +158,7 @@ public class CylindricalSatelliteTracking extends
ConicSatelliteTracking {
final double dx_dφ = 0;
final double dy_dλ = 0;
- final double dy_dφ = ((cos(φ) / sin_i)
*(1/sqrt(1-sinφ_sini*sinφ_sini))) // derivative of (-dλ/dφ)
- * ( p2_on_p1 - ((1+tan_dλ*tan_dλ)*cos_i/(1+λt*λt) ) );
+ final double dy_dφ = vector_L[1]; //dL/dφ
//======================================================================
return new Matrix2(dx_dλ, dx_dφ,
