This is an automated email from the ASF dual-hosted git repository.
desruisseaux pushed a commit to branch geoapi-4.0
in repository https://gitbox.apache.org/repos/asf/sis.git
commit 78a95a0f2530dc0a3069069ae22e51121f4cab8b
Author: Martin Desruisseaux <martin.desruisse...@geomatys.com>
AuthorDate: Fri Jan 28 22:23:56 2022 +0100
Add an `isIdentity()` method.
---
.../operation/transform/RotatedPole.java | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)
diff --git
a/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/RotatedPole.java
b/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/RotatedPole.java
index fb826dd..6e613fd 100644
---
a/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/RotatedPole.java
+++
b/core/sis-referencing/src/main/java/org/apache/sis/referencing/operation/transform/RotatedPole.java
@@ -118,6 +118,9 @@ public class RotatedPole extends AbstractMathTransform2D
implements Serializable
/**
* Creates the inverse of the given forward operation.
+ * The new pole latitude is φ<sub>p</sub> = (180° − φ<sub>forward</sub>).
+ * We get this effect be inverting the sign of {@link #cosφp} while
keeping {@link #sinφp} unchanged.
+ * Note that this is compatible with {@link #isIdentity()} implementation.
*
* @see #inverse()
*/
@@ -150,7 +153,7 @@ public class RotatedPole extends AbstractMathTransform2D
implements Serializable
i = 3 - i;
}
double value = -((Number) ((ParameterValue<?>)
values.get(i)).getValue()).doubleValue();
- if (i == 0) value = Math.IEEEremainder(value + 180, 360);
+ if (i == 0) value = IEEEremainder(value + 180, 360);
target.setValue(value);
return true;
}
@@ -169,7 +172,7 @@ public class RotatedPole extends AbstractMathTransform2D
implements Serializable
* @param pa angle of rotation in degrees about the new polar axis
measured clockwise when
* looking from the southern to the northern pole.
*/
- protected RotatedPole(final boolean south, double φp, double λp, double
pa) {
+ protected RotatedPole(final boolean south, final double φp, final double
λp, final double pa) {
context = new ContextualParameters(
south ? RotatedSouthPole.PARAMETERS
: RotatedNorthPole.PARAMETERS, 2, 2);
@@ -329,6 +332,21 @@ public class RotatedPole extends AbstractMathTransform2D
implements Serializable
}
/**
+ * Tests whether this transform does not move any points.
+ *
+ * @return {@code true} if this transform is (at least approximately) the
identity transform.
+ */
+ @Override
+ public boolean isIdentity() {
+ return sinφp == -1;
+ /*
+ * We do not test `cosφp` because that value may be small but
non-zero, especially since there is no exact
+ * representation of `cos(π/2)`. Testing `sinφp == -1` is a way to
allow for a small tolerance around π/2.
+ * This policy is also needed for consistency with
`RotatedPole(RotatedPole)` implementation.
+ */
+ }
+
+ /**
* Compares the specified object with this math transform for equality.
*
* @param object the object to compare with this transform.
