From 8d0b513e6b0e75e66103e4fd1ba9983f3ee51714 Mon Sep 17 00:00:00 2001
From: Luc Maisonobe <luc@orekit.org>
Date: Wed, 2 Apr 2014 11:20:30 +0200
Subject: [PATCH] Slight speed-up with a dedicated pointOnGround method.
---
.../org/orekit/rugged/core/ExtendedEllipsoid.java | 13 +++++++++++++
.../org/orekit/rugged/core/IgnoreDEMAlgorithm.java | 3 +--
.../rugged/core/duvenhage/DuvenhageAlgorithm.java | 3 +--
3 files changed, 15 insertions(+), 4 deletions(-)
diff --git a/src/main/java/org/orekit/rugged/core/ExtendedEllipsoid.java b/src/main/java/org/orekit/rugged/core/ExtendedEllipsoid.java
index bb267bd3..e092e05a 100644
--- a/src/main/java/org/orekit/rugged/core/ExtendedEllipsoid.java
+++ b/src/main/java/org/orekit/rugged/core/ExtendedEllipsoid.java
@@ -16,6 +16,7 @@
*/
package org.orekit.rugged.core;
+import org.apache.commons.math3.geometry.euclidean.threed.Line;
import org.apache.commons.math3.geometry.euclidean.threed.Vector3D;
import org.apache.commons.math3.util.FastMath;
import org.orekit.bodies.GeodeticPoint;
@@ -145,6 +146,18 @@ public class ExtendedEllipsoid extends OneAxisEllipsoid {
}
+ /** Get point on ground along a pixel line of sight.
+ * @param position pixel position (in body frame)
+ * @param los pixel line-of-sight, not necessarily normalized (in body frame)
+ * @return point on ground
+ * @exception OrekitException if no such point exists (typically line-of-sight missing body)
+ */
+ public GeodeticPoint pointOnGround(final Vector3D position, final Vector3D los)
+ throws OrekitException {
+ return getIntersectionPoint(new Line(position, new Vector3D(1, position, 1e6, los), 1.0e-12),
+ position, getBodyFrame(), null);
+ }
+
/** Get point at some altitude along a pixel line of sight.
* @param position pixel position (in body frame)
* @param los pixel line-of-sight, not necessarily normalized (in body frame)
diff --git a/src/main/java/org/orekit/rugged/core/IgnoreDEMAlgorithm.java b/src/main/java/org/orekit/rugged/core/IgnoreDEMAlgorithm.java
index 5dfa5fd3..6f04136e 100644
--- a/src/main/java/org/orekit/rugged/core/IgnoreDEMAlgorithm.java
+++ b/src/main/java/org/orekit/rugged/core/IgnoreDEMAlgorithm.java
@@ -48,8 +48,7 @@ public class IgnoreDEMAlgorithm implements IntersectionAlgorithm {
final Vector3D position, final Vector3D los)
throws RuggedException {
try {
- return ellipsoid.transform(ellipsoid.pointAtAltitude(position, los, 0.0),
- ellipsoid.getBodyFrame(), null);
+ return ellipsoid.pointOnGround(position, los);
} catch (OrekitException oe) {
// this should never happen
throw new RuggedException(oe, oe.getSpecifier(), oe.getParts());
diff --git a/src/main/java/org/orekit/rugged/core/duvenhage/DuvenhageAlgorithm.java b/src/main/java/org/orekit/rugged/core/duvenhage/DuvenhageAlgorithm.java
index dca15184..b81cb98d 100644
--- a/src/main/java/org/orekit/rugged/core/duvenhage/DuvenhageAlgorithm.java
+++ b/src/main/java/org/orekit/rugged/core/duvenhage/DuvenhageAlgorithm.java
@@ -63,8 +63,7 @@ public class DuvenhageAlgorithm implements IntersectionAlgorithm {
try {
// compute intersection with ellipsoid
- final Vector3D p0 = ellipsoid.pointAtAltitude(position, los, 0.0);
- final GeodeticPoint gp0 = ellipsoid.transform(p0, ellipsoid.getBodyFrame(), null);
+ final GeodeticPoint gp0 = ellipsoid.pointOnGround(position, los);
// locate the entry tile along the line-of-sight
MinMaxTreeTile tile = cache.getTile(gp0.getLatitude(), gp0.getLongitude());
--
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