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 38b9d8fc69bcede94dca2a7d19dc2b7621a79333
Author: Martin Desruisseaux <martin.desruisse...@geomatys.com>
AuthorDate: Wed Oct 17 18:29:37 2018 +0200
Fix rounding error when converting 46°57'8.66" to decimal degrees.
The slight rounding error become a 4 cm error in some map projections.
---
.../java/org/apache/sis/internal/util/Numerics.java | 2 +-
.../org/apache/sis/measure/SexagesimalConverter.java | 20 +++++++++++++++++++-
.../apache/sis/measure/SexagesimalConverterTest.java | 13 ++++++++++++-
3 files changed, 32 insertions(+), 3 deletions(-)
diff --git
a/core/sis-utility/src/main/java/org/apache/sis/internal/util/Numerics.java
b/core/sis-utility/src/main/java/org/apache/sis/internal/util/Numerics.java
index 5e50833..a231706 100644
--- a/core/sis-utility/src/main/java/org/apache/sis/internal/util/Numerics.java
+++ b/core/sis-utility/src/main/java/org/apache/sis/internal/util/Numerics.java
@@ -71,7 +71,7 @@ public final class Numerics extends Static {
* {@link org.apache.sis.util.ComparisonMode#APPROXIMATIVE}.
*
* <p>Historically, this was the relative tolerance threshold for
considering two
- * matrixes as equal. This value has been determined empirically in order
to allow
+ * matrices as equal. This value has been determined empirically in order
to allow
* {@code
org.apache.sis.referencing.operation.transform.ConcatenatedTransform} to
* detect the cases where two {@link
org.apache.sis.referencing.operation.transform.LinearTransform}
* are equal for practical purpose. This threshold can be used as
below:</p>
diff --git
a/core/sis-utility/src/main/java/org/apache/sis/measure/SexagesimalConverter.java
b/core/sis-utility/src/main/java/org/apache/sis/measure/SexagesimalConverter.java
index 494de7d..dc1dbaf 100644
---
a/core/sis-utility/src/main/java/org/apache/sis/measure/SexagesimalConverter.java
+++
b/core/sis-utility/src/main/java/org/apache/sis/measure/SexagesimalConverter.java
@@ -41,7 +41,7 @@ import static org.apache.sis.math.MathFunctions.truncate;
* This class and all inner classes are immutable, and thus inherently
thread-safe.
*
* @author Martin Desruisseaux (IRD, Geomatys)
- * @version 0.8
+ * @version 1.0
* @since 0.3
* @module
*/
@@ -272,6 +272,22 @@ class SexagesimalConverter extends AbstractConverter {
}
/**
+ * After calculation of the remaining seconds or minutes, trims the
rounding errors presumably
+ * caused by rounding errors in floating point arithmetic. This is
required for avoiding the
+ * following conversion issue:
+ *
+ * <ol>
+ * <li>Sexagesimal value: 46.570866 (from 46°57'8.66"N in EPSG:2056
projected CRS)</li>
+ * <li>value * 10000 = 465708.66000000003</li>
+ * <li>deg = 46, min = 57, deg = 8.660000000032596</li>
+ * </ol>
+ */
+ private static double fixRoundingError(final double remainder) {
+ final double c = Math.rint(remainder * 1E+6) / 1E+6;
+ return (Math.abs(remainder - c) < 1E-9) ? c : remainder;
+ }
+
+ /**
* Performs a conversion from sexagesimal degrees to fractional
degrees.
*
* @throws IllegalArgumentException If the given angle can not be
converted.
@@ -283,11 +299,13 @@ class SexagesimalConverter extends AbstractConverter {
sec = angle * divider;
deg = truncate(sec/10000); sec -= 10000*deg;
min = truncate(sec/ 100); sec -= 100*min;
+ sec = fixRoundingError(sec);
} else {
sec = 0;
min = angle * divider;
deg = truncate(min / 100);
min -= deg * 100;
+ min = fixRoundingError(min);
}
if (min <= -60 || min >= 60) { // Do
not enter for NaN
if (Math.abs(Math.abs(min) - 100) <= (EPS * 100)) {
diff --git
a/core/sis-utility/src/test/java/org/apache/sis/measure/SexagesimalConverterTest.java
b/core/sis-utility/src/test/java/org/apache/sis/measure/SexagesimalConverterTest.java
index d7187e8..f6c385e 100644
---
a/core/sis-utility/src/test/java/org/apache/sis/measure/SexagesimalConverterTest.java
+++
b/core/sis-utility/src/test/java/org/apache/sis/measure/SexagesimalConverterTest.java
@@ -30,7 +30,7 @@ import static org.apache.sis.test.Assert.*;
* Test the {@link SexagesimalConverter} class.
*
* @author Martin Desruisseaux (Geomatys)
- * @version 0.8
+ * @version 1.0
* @since 0.3
* @module
*/
@@ -93,6 +93,17 @@ public final strictfp class SexagesimalConverterTest extends
TestCase {
}
/**
+ * Tests the fix for rounding error in conversion of 46°57'8.66".
+ * This fix is necessary for avoiding a 4 cm error with Apache SIS
+ * construction of EPSG:2056 projected CRS.
+ */
+ @Test
+ public void testRoundingErrorFix() {
+ final UnitConverter c = DMS.getConverterTo(Units.DEGREE);
+ assertEquals(46.95240555555556, c.convert(46.570866), STRICT);
+ }
+
+ /**
* Verifies the unit symbols.
*/
@Test
