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 0a53a466e34dcb3ab390f4f1313aff3408215985
Author: Martin Desruisseaux <martin.desruisse...@geomatys.com>
AuthorDate: Fri Feb 28 12:17:02 2025 +0100
Add a safety against singular matrices read from GeoTIFF files.
---
.../sis/referencing/operation/matrix/Matrices.java | 62 ++++++++++++++++++----
.../referencing/operation/matrix/MatricesTest.java | 16 ++++++
.../geotiff/reader/GridGeometryBuilder.java | 13 ++++-
.../sis/storage/geotiff/writer/GeoEncoder.java | 6 ++-
4 files changed, 84 insertions(+), 13 deletions(-)
diff --git
a/endorsed/src/org.apache.sis.referencing/main/org/apache/sis/referencing/operation/matrix/Matrices.java
b/endorsed/src/org.apache.sis.referencing/main/org/apache/sis/referencing/operation/matrix/Matrices.java
index f058efe7bf..85960cec2e 100644
---
a/endorsed/src/org.apache.sis.referencing/main/org/apache/sis/referencing/operation/matrix/Matrices.java
+++
b/endorsed/src/org.apache.sis.referencing/main/org/apache/sis/referencing/operation/matrix/Matrices.java
@@ -75,7 +75,7 @@ import org.opengis.coordinate.MismatchedDimensionException;
* </ul>
*
* @author Martin Desruisseaux (IRD, Geomatys)
- * @version 1.4
+ * @version 1.5
*
* @see org.apache.sis.parameter.TensorParameters
*
@@ -891,6 +891,46 @@ public final class Matrices extends Static {
return changed;
}
+ /**
+ * Forces the matrix to have at least one non-zero coefficient in every
row, assuming an affine transform.
+ * The last column (the translation terms) and the last row (the [0 0 … 1]
terms) are ignored.
+ * If a row contains only zero values (ignoring the translation term),
+ * then this method sets one element of that row to the given {@code
defaultValue}.
+ * That modification occurs in the first free column, i.e. a column having
no non-zero value.
+ * If no such free column is found, then this method stops the operation
and returns {@code false}.
+ *
+ * @param matrix the matrix in which to force non-zero scale
factors. Will be modified in-place.
+ * @param defaultValue the scale factor to assign to rows that do not
have a non-zero scale factor.
+ * @return {@code true} on success (including when this method does
nothing), or
+ * {@code false} if this method cannot complete the operation.
+ *
+ * @since 1.5
+ */
+ public static boolean forceNonZeroScales(final Matrix matrix, final double
defaultValue) {
+ final int numCol = matrix.getNumCol() - 1;
+ final int numRow = matrix.getNumRow() - 1;
+ int freeColumn = 0;
+okay: for (int j=0; j<numRow; j++) {
+ for (int i=0; i<numCol; i++) {
+ if (matrix.getElement(j, i) != 0) {
+ continue okay;
+ }
+ }
+search: while (freeColumn < numCol) {
+ for (int i=0; i<numRow; i++) {
+ if (matrix.getElement(i, freeColumn) != 0) {
+ freeColumn++;
+ continue search;
+ }
+ }
+ matrix.setElement(j, freeColumn++, defaultValue);
+ continue okay;
+ }
+ return false;
+ }
+ return true;
+ }
+
/**
* Returns {@code true} if the given matrix is likely to use extended
precision.
* A value of {@code true} is not a guarantee that the matrix uses
extended precision,
@@ -1000,7 +1040,7 @@ public final class Matrices extends Static {
if (numRow == numCol) {
return Solver.inverse(matrix);
}
- final NonSquareMatrix result = new NonSquareMatrix(numRow, numCol,
false);
+ final var result = new NonSquareMatrix(numRow, numCol, false);
result.setMatrix(matrix);
return result.inverse();
}
@@ -1221,13 +1261,13 @@ public final class Matrices extends Static {
public static String toString(final Matrix matrix) {
final int numRow = matrix.getNumRow();
final int numCol = matrix.getNumCol();
- final String[] elements = new String [numCol * numRow];
// String representation of matrix values.
- final boolean[] noFractionDigits = new boolean[numCol * numRow];
// Whether to remove the trailing ".0" for a given number.
- final boolean[] hasDecimalSeparator = new boolean[numCol];
// Whether the column has at least one number where fraction digits are shown.
- final byte[] maximumFractionDigits = new byte [numCol];
// The greatest number of fraction digits found in a column.
- final byte[] maximumPaddingZeros = new byte [numCol * numRow];
// Maximal number of zeros that we can append before to exceed the IEEE 754
accuracy.
- final byte[] widthBeforeFraction = new byte [numCol];
// Number of characters before the fraction digits: spacing + ('-') +
integerDigits + '.'
- final byte[] columnWidth = new byte [numCol];
// Total column width.
+ final var elements = new String [numCol * numRow]; //
String representation of matrix values.
+ final var noFractionDigits = new boolean[numCol * numRow]; //
Whether to remove the trailing ".0" for a given number.
+ final var hasDecimalSeparator = new boolean[numCol]; //
Whether the column has at least one number where fraction digits are shown.
+ final var maximumFractionDigits = new byte [numCol]; //
The greatest number of fraction digits found in a column.
+ final var maximumPaddingZeros = new byte [numCol * numRow]; //
Maximal number of zeros that we can append before to exceed the IEEE 754
accuracy.
+ final var widthBeforeFraction = new byte [numCol]; //
Number of characters before the fraction digits: spacing + ('-') +
integerDigits + '.'
+ final var columnWidth = new byte [numCol]; //
Total column width.
int totalWidth = 1;
/*
* Create now the string representation of all matrix elements and
measure the width
@@ -1290,9 +1330,9 @@ public final class Matrices extends Static {
* Now append the formatted elements with the appropriate number of
spaces before each value,
* and trailling zeros after each value except ±0, ±1, NaN and
infinities.
*/
- final String lineSeparator = System.lineSeparator();
+ final String lineSeparator = System.lineSeparator();
final CharSequence whiteLine = CharSequences.spaces(totalWidth);
- final StringBuilder buffer = new StringBuilder((totalWidth + 2 +
lineSeparator.length()) * (numRow + 2));
+ final var buffer = new StringBuilder((totalWidth + 2 +
lineSeparator.length()) * (numRow + 2));
buffer.append('┌').append(whiteLine).append('┐').append(lineSeparator);
int flatIndex = 0;
for (int j=0; j<numRow; j++) {
diff --git
a/endorsed/src/org.apache.sis.referencing/test/org/apache/sis/referencing/operation/matrix/MatricesTest.java
b/endorsed/src/org.apache.sis.referencing/test/org/apache/sis/referencing/operation/matrix/MatricesTest.java
index 29b28f520f..252ae8862c 100644
---
a/endorsed/src/org.apache.sis.referencing/test/org/apache/sis/referencing/operation/matrix/MatricesTest.java
+++
b/endorsed/src/org.apache.sis.referencing/test/org/apache/sis/referencing/operation/matrix/MatricesTest.java
@@ -442,6 +442,22 @@ public final class MatricesTest extends TestCase {
}), matrix);
}
+ /**
+ * Tests {@link Matrices#forceNonZeroScales(Matrix, double)}.
+ */
+ public void testForceNonZeroScales() {
+ MatrixSIS matrix = Matrices.create(4, 4, new double[] {
+ 2, 0, 0, 8,
+ 0, 0, 4, 7,
+ 0, 0, 0, 6,
+ 0, 0, 0, 1
+ });
+ MatrixSIS expected = matrix.clone();
+ expected.setElement(2, 1, 3);
+ assertTrue(Matrices.forceNonZeroScales(matrix, 3));
+ assertEquals(expected, matrix);
+ }
+
/**
* Tests {@link Matrices#equals(Matrix, Matrix, double, boolean)}.
*/
diff --git
a/endorsed/src/org.apache.sis.storage.geotiff/main/org/apache/sis/storage/geotiff/reader/GridGeometryBuilder.java
b/endorsed/src/org.apache.sis.storage.geotiff/main/org/apache/sis/storage/geotiff/reader/GridGeometryBuilder.java
index bb64c6df01..7a7366e899 100644
---
a/endorsed/src/org.apache.sis.storage.geotiff/main/org/apache/sis/storage/geotiff/reader/GridGeometryBuilder.java
+++
b/endorsed/src/org.apache.sis.storage.geotiff/main/org/apache/sis/storage/geotiff/reader/GridGeometryBuilder.java
@@ -25,6 +25,7 @@ import org.opengis.metadata.spatial.DimensionNameType;
import org.opengis.parameter.ParameterNotFoundException;
import org.opengis.referencing.NoSuchAuthorityCodeException;
import org.opengis.referencing.crs.CoordinateReferenceSystem;
+import org.opengis.referencing.operation.Matrix;
import org.opengis.referencing.operation.MathTransform;
import org.opengis.referencing.operation.MathTransformFactory;
import org.opengis.referencing.operation.TransformException;
@@ -76,6 +77,14 @@ import org.apache.sis.math.Vector;
* @author Martin Desruisseaux (Geomatys)
*/
public final class GridGeometryBuilder extends GeoKeysLoader {
+ /**
+ * Default scale factory to apply if a row in the model transformation
contains only zero values.
+ * The matrix in a GeoTIFF file is always of size 4×4 even if the
<abbr>CRS</abbr> is two-dimensional.
+ * In the latter case, the matrix row for the third dimension has only
zero values. That row should be
+ * discarded when building the final {@link GridGeometry}, but there is
sometime inconsistency between
+ * the number of <abbr>CRS</abbr> dimensions and which matrix rows have
been assigned non-zero values.
+ */
+ private static final double DEFAULT_SCALE_FACTOR = 1;
//
╔════════════════════════════════════════════════════════════════════════════════╗
// ║
║
@@ -300,7 +309,9 @@ public final class GridGeometryBuilder extends
GeoKeysLoader {
try {
MathTransform gridToCRS = null;
if (affine != null) {
- gridToCRS =
factory.createAffineTransform(Matrices.resizeAffine(affine, ++n, n));
+ final Matrix m = Matrices.resizeAffine(affine, ++n, n);
+ Matrices.forceNonZeroScales(m, DEFAULT_SCALE_FACTOR);
+ gridToCRS = factory.createAffineTransform(m);
} else if (modelTiePoints != null) {
pixelIsPoint = true;
gridToCRS = Localization.nonLinear(modelTiePoints);
diff --git
a/endorsed/src/org.apache.sis.storage.geotiff/main/org/apache/sis/storage/geotiff/writer/GeoEncoder.java
b/endorsed/src/org.apache.sis.storage.geotiff/main/org/apache/sis/storage/geotiff/writer/GeoEncoder.java
index fc61bfaef5..a0d4db0378 100644
---
a/endorsed/src/org.apache.sis.storage.geotiff/main/org/apache/sis/storage/geotiff/writer/GeoEncoder.java
+++
b/endorsed/src/org.apache.sis.storage.geotiff/main/org/apache/sis/storage/geotiff/writer/GeoEncoder.java
@@ -97,7 +97,11 @@ public final class GeoEncoder {
/**
* Size of the model transformation matrix, in number of rows and columns.
- * This size is fixed by the GeoTIFF specification.
+ * This size is fixed by the GeoTIFF specification. If some rows need to
+ * be added for filling the space, they will be filled with zero values
+ * (i.e., the matrix will be singular until the reader removes those rows).
+ *
+ * @see
org.apache.sis.storage.geotiff.reader.GridGeometryBuilder#DEFAULT_SCALE_FACTOR
*/
private static final int MATRIX_SIZE = 4;
