Class PolarToCartesian

java.lang.Object

org.apache.sis.io.wkt.FormattableObject

org.apache.sis.referencing.operation.transform.AbstractMathTransform

org.apache.sis.referencing.operation.transform.CoordinateSystemTransform

org.apache.sis.referencing.operation.transform.PolarToCartesian

All Implemented Interfaces:

Serializable, Parameterized, LenientComparable, org.opengis.referencing.operation.MathTransform

final class PolarToCartesian
extends CoordinateSystemTransform
implements Serializable

Conversions from polar coordinates to two-dimensional Cartesian coordinates. This conversion assumes that there is no datum change. Source axis order is:

• Radius (r)
• Angle (θ)
• Height (z) in the cylindrical case (see below)

Target axis order is:

• x in the direction of θ = 0°
• y in the direction of θ = 90°
• z in the same direction than the source (cylindrical case only - see below)

Axis order shall match the order defined by Normalizer in org.apache.sis.referencing.cs package.

Note: We do not provide explicit CylindricalToCartesian implementation. Instead, the cylindrical case is implemented by the polar case with a PassThroughTransform for the height. This allows Apache SIS to use the optimization implemented by PassThroughTransform when for example a concatenated transform is dropping the z axis.

Since:

0.7

Version:

0.7

Nested Class Summary

Nested classes/interfaces inherited from class AbstractMathTransform

AbstractMathTransform.Inverse

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static final PolarToCartesian	INSTANCE	The singleton instance expecting input coordinates in radians.
private static final long	serialVersionUID	For cross-version compatibility.

Fields inherited from class CoordinateSystemTransform

context

Fields inherited from class AbstractMathTransform

MAXIMUM_BUFFER_SIZE, MAXIMUM_FAILURES

Constructor Summary

Constructors

Modifier	Constructor	Description
private	PolarToCartesian()	Creates the singleton instance.

Method Summary

Modifier and Type	Method	Description
org.opengis.referencing.operation.MathTransform	inverse()	Returns the inverse of this transform.
private Object	readResolve()	Returns the singleton instance on deserialization.
org.opengis.referencing.operation.Matrix	transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, boolean derivate)	Converts a single coordinate and optionally computes the derivative.
void	transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts)	Converts an array of coordinates.

Methods inherited from class CoordinateSystemTransform

completeTransform, create, getContextualParameters, getParameterValues, getSourceDimensions, getTargetDimensions, passthrough

Methods inherited from class AbstractMathTransform

beforeFormat, computeHashCode, derivative, equals, equals, formatTo, getDomain, getParameterDescriptors, hashCode, isIdentity, isInverseEquals, mismatchedDimension, transform, transform, transform, transform, tryConcatenate

Methods inherited from class FormattableObject

print, toString, toString, toWKT

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.opengis.referencing.operation.MathTransform

toWKT

Field Details

serialVersionUID

private static final long serialVersionUID

For cross-version compatibility.

See Also:

• Constant Field Values

INSTANCE

static final PolarToCartesian INSTANCE

The singleton instance expecting input coordinates in radians. For the instance expecting input coordinates in degrees, use CoordinateSystemTransform.create(MathTransformFactory, CoordinateSystem, CoordinateSystem, ThreadLocal) instead.

Constructor Details

PolarToCartesian

private PolarToCartesian()

Creates the singleton instance. Input coordinates are in radians.

Method Details

readResolve

private Object readResolve()
                    throws ObjectStreamException

Returns the singleton instance on deserialization.

Throws:

ObjectStreamException

inverse

public org.opengis.referencing.operation.MathTransform inverse()

Returns the inverse of this transform.

Specified by:

inverse in interface org.opengis.referencing.operation.MathTransform

Overrides:

inverse in class AbstractMathTransform

transform

public org.opengis.referencing.operation.Matrix transform(double[] srcPts,
 int srcOff,
 double[] dstPts,
 int dstOff,
 boolean derivate)

Converts a single coordinate and optionally computes the derivative.

Specified by:

transform in class AbstractMathTransform

Parameters:

srcPts - the array containing the source coordinates (cannot be null).

srcOff - the offset to the point to be transformed in the source array.

dstPts - the array into which the transformed coordinates is returned. May be the same than srcPts. May be null if only the derivative matrix is desired.

dstOff - the offset to the location of the transformed point that is stored in the destination array.

derivate - true for computing the derivative, or false if not needed.

Returns:

the matrix of the transform derivative at the given source position, or null if the derivate argument is false.

See Also:

• AbstractMathTransform.derivative(DirectPosition)
• AbstractMathTransform.transform(DirectPosition, DirectPosition)
• MathTransforms.derivativeAndTransform(MathTransform, double[], int, double[], int)

transform

public void transform(double[] srcPts,
 int srcOff,
 double[] dstPts,
 int dstOff,
 int numPts)

Converts an array of coordinates. This method performs the same conversion than transform(double[], int, double[], int, boolean), but the formulas are repeated here for performance reasons.

Specified by:

transform in interface org.opengis.referencing.operation.MathTransform

Overrides:

transform in class AbstractMathTransform

Parameters:

srcPts - the array containing the source point coordinates.

srcOff - the offset to the first point to be transformed in the source array.

dstPts - the array into which the transformed point coordinates are returned. May be the same than srcPts.

dstOff - the offset to the location of the first transformed point that is stored in the destination array.

numPts - the number of point objects to be transformed.