Examples with TransferFunction org.apache.sis.referencing.operation.transform.TransferFunction used on opensource projects

Example 1 with TransferFunction

use of org.apache.sis.referencing.operation.transform.TransferFunction in project sis by apache.

the class SampleDimensionTest method testQuantitativeWithMissingValues.

/**
 * Tests a sample dimension having one quantitative category and a few "no data" values.
 * Expected value:
 *
 * {@preformat text
 * ┌────────────┬──────────────────┬─────────────┐
 * │   Values   │     Measures     │    Name     │
 * ╞════════════╧══════════════════╧═════════════╡
 * │ Temperature                                 │
 * ├────────────┬──────────────────┬─────────────┤
 * │         0  │ NaN #0           │ Fill value  │
 * │         1  │ NaN #1           │ Clouds      │
 * │ [10 … 200) │ [6.00 … 25.00)°C │ Temperature │
 * │       255  │ NaN #255         │ Lands       │
 * └────────────┴──────────────────┴─────────────┘
 * }
 */
@Test
public void testQuantitativeWithMissingValues() {
    final int lower = 10;
    final int upper = 200;
    final double scale = 0.1;
    final double offset = 5.0;
    final SampleDimension dimension = new SampleDimension.Builder().setBackground(null, // Default to "Fill value" name, potentially localized.
    0).addQualitative("Clouds", 1).addQualitative("Lands", 255).addQuantitative("Temperature", lower, upper, scale, offset, Units.CELSIUS).build();
    assertEquals("name", "Temperature", String.valueOf(dimension.getName()));
    assertEquals("background", 0, dimension.getBackground().get());
    final Set<Number> nodataValues = dimension.getNoDataValues();
    assertArrayEquals("nodataValues", new Integer[] { 0, 1, 255 }, nodataValues.toArray());
    NumberRange<?> range = dimension.getSampleRange().get();
    assertEquals("minimum", 0, range.getMinDouble(), STRICT);
    assertEquals("maximum", 255, range.getMaxDouble(), STRICT);
    range = dimension.getMeasurementRange().get();
    assertEquals("minimum", lower * scale + offset, range.getMinDouble(true), CategoryTest.EPS);
    assertEquals("maximum", upper * scale + offset, range.getMaxDouble(false), CategoryTest.EPS);
    assertEquals("units", Units.CELSIUS, dimension.getUnits().get());
    final TransferFunction tr = dimension.getTransferFunctionFormula().get();
    assertFalse("identity", dimension.getTransferFunction().get().isIdentity());
    assertFalse("identity", tr.getTransform().isIdentity());
    assertEquals("scale", scale, tr.getScale(), STRICT);
    assertEquals("offset", offset, tr.getOffset(), STRICT);
    /*
         * Verifies SampleDimension properties after we converted integers to real values.
         */
    final SampleDimension converted = dimension.forConvertedValues(true);
    assertNotSame(dimension, converted);
    assertSame(dimension, dimension.forConvertedValues(false));
    assertSame(dimension, converted.forConvertedValues(false));
    assertSame(converted, converted.forConvertedValues(true));
    assertSame(range, converted.getSampleRange().get());
    assertTrue("identity", converted.getTransferFunction().get().isIdentity());
    assertTrue("background", Double.isNaN(converted.getBackground().get().doubleValue()));
    final Iterator<Number> it = converted.getNoDataValues().iterator();
    assertEquals("nodataValues", 0, MathFunctions.toNanOrdinal(it.next().floatValue()));
    assertEquals("nodataValues", 1, MathFunctions.toNanOrdinal(it.next().floatValue()));
    assertEquals("nodataValues", 255, MathFunctions.toNanOrdinal(it.next().floatValue()));
    assertFalse("nodataValues", it.hasNext());
}

Example 2 with TransferFunction

use of org.apache.sis.referencing.operation.transform.TransferFunction in project sis by apache.

the class Axis method read.

/**
 * Returns the coordinates in the localization grid, excluding some trailing NaN values if any.
 * This method typically returns a cached vector if the coordinates have already been read.
 *
 * @throws IOException if an error occurred while reading the data.
 * @throws DataStoreException if a logical error occurred.
 */
final Vector read() throws IOException, DataStoreException {
    final TransferFunction tr = coordinates.getTransferFunction();
    if (TransferFunctionType.LINEAR.equals(tr.getType())) {
        Vector data = coordinates.read();
        if (gridSizes != null) {
            // Trim trailing NaN values.
            data = data.subList(0, getSizeProduct(0));
        }
        // Apply scale and offset attributes, if any.
        data = data.transform(tr.getScale(), tr.getOffset());
        return data;
    } else {
        throw new DataStoreException(coordinates.resources().getString(Resources.Keys.CanNotUseAxis_1, getName()));
    }
}

Example 3 with TransferFunction

use of org.apache.sis.referencing.operation.transform.TransferFunction in project sis by apache.

the class GCOM_W method transferFunction.

/**
 * Builds the function converting values from their packed formats in the variable to "real" values.
 * This method is invoked only if {@link #validRange(Variable)} returned a non-null value.
 *
 * @param  data  the variable from which to determine the transfer function.
 * @return a transfer function built from the attributes defined in the given variable.
 */
@Override
public TransferFunction transferFunction(final Variable data) {
    final TransferFunction tr = super.transferFunction(data);
    if (tr.isIdentity()) {
        final double slope = data.getAttributeAsNumber("SCALE FACTOR");
        final double offset = data.getAttributeAsNumber("OFFSET");
        if (Double.isFinite(slope))
            tr.setScale(slope);
        if (Double.isFinite(offset))
            tr.setOffset(offset);
    }
    return tr;
}

Example 4 with TransferFunction

use of org.apache.sis.referencing.operation.transform.TransferFunction in project sis by apache.

the class Convention method transferFunction.

/**
 * Builds the function converting values from their packed formats in the variable to "real" values.
 * The transfer function is typically built from the {@code "scale_factor"} and {@code "add_offset"}
 * attributes associated to the given variable, but other conventions could use different attributes.
 * The returned function will be a component of the {@link org.apache.sis.coverage.SampleDimension}
 * to be created for each variable.
 *
 * <p>This method is invoked in contexts where a transfer function is assumed to exist, for example
 * because {@link #validRange(Variable)} returned a non-null value. Consequently this method shall
 * never return {@code null}, but can return the identity function.</p>
 *
 * @param  data  the variable from which to determine the transfer function.
 *               This is usually a variable containing raster data.
 *
 * @return a transfer function built from the attributes defined in the given variable. Never null;
 *         if no information is found in the given {@code data} variable, then the return value
 *         shall be an identity function.
 */
public TransferFunction transferFunction(final Variable data) {
    /*
         * If scale_factor and/or add_offset variable attributes are present, then this is
         * a "packed" variable. Otherwise the transfer function is the identity transform.
         */
    final TransferFunction tr = new TransferFunction();
    final double scale = data.getAttributeAsNumber(CDM.SCALE_FACTOR);
    final double offset = data.getAttributeAsNumber(CDM.ADD_OFFSET);
    if (!Double.isNaN(scale))
        tr.setScale(scale);
    if (!Double.isNaN(offset))
        tr.setOffset(offset);
    return tr;
}

Example 5 with TransferFunction

use of org.apache.sis.referencing.operation.transform.TransferFunction in project sis by apache.

the class SampleDimension method getTransferFunctionFormula.

/**
 * Returns the scale factor and offset of the transfer function.
 * The formula returned by this method does <strong>not</strong> take
 * "{@linkplain #getNoDataValues() no data values}" in account.
 * For a more generic transfer function, see {@link #getTransferFunction()}.
 *
 * @return a description of the part of the transfer function working on real numbers.
 * @throws IllegalStateException if the transfer function can not be simplified in a form representable
 *         by {@link TransferFunction}.
 */
public Optional<TransferFunction> getTransferFunctionFormula() {
    MathTransform1D tr = null;
    for (final Category category : categories) {
        final Optional<MathTransform1D> c = category.getTransferFunction();
        if (c.isPresent()) {
            if (tr == null) {
                tr = c.get();
            } else if (!tr.equals(c.get())) {
                throw new IllegalStateException(Resources.format(Resources.Keys.CanNotSimplifyTransferFunction_1));
            }
        }
    }
    if (tr == null) {
        return Optional.empty();
    }
    final TransferFunction f = new TransferFunction();
    try {
        f.setTransform(tr);
    } catch (IllegalArgumentException e) {
        throw new IllegalStateException(Resources.format(Resources.Keys.CanNotSimplifyTransferFunction_1, e));
    }
    return Optional.of(f);
}