com.luciad.tea

Terrain Analysis EngineClass TLcdLOSPropagationFunctionFixedHeight

java.lang.Object

com.luciad.tea.TLcdLOSPropagationFunctionFixedHeight

All Implemented Interfaces:

ILcdLOSPropagationFunction

public class TLcdLOSPropagationFunctionFixedHeight
extends Object
implements ILcdLOSPropagationFunction

Computes the visibility of points at a fixed height from the center point of a line-of-sight coverage.

This propagation function needs an ILcdLOSPropagationFunction on which it will base its line-of-sight computations. The radar propagation function computes the minimal heights from which one is visible. These heights, combined with the cone of visibility, are compared to the given fixed height, resulting in one of the following values:

• VISIBLE: for points where the object is visible.
• INVISIBLE: for points where the object is invisible.
• CONE_OF_SILENCE: for the points corresponding to the cone of silence around the given point.
• UNKNOWN: for points where the visibility is unknown. For example when no elevation data or invalid data was found at that point.

The following image gives a visual explanation of this propagation function. The green line denotes the visible area at the given fixed height, the red line corresponds to the invisible area and the blue line to the area represented by the cone of silence. The thin black line corresponds to the line-of-sight coverage matrix, needed by this function.

Field Summary

Fields

Modifier and Type	Field and Description
static int	CONE_OF_SILENCE The resulting value for the points corresponding to the cone of silence around the given point.
static int	INVISIBLE The resulting value for points where the object is invisible due to the obstruction of the terrain.
static int	UNKNOWN The resulting value for points where the visibility is unknown.
static int	VISIBLE The resulting value for points where the object is visible.

Constructor Summary

Constructors

Constructor and Description
TLcdLOSPropagationFunctionFixedHeight(ILcdLOSRadarPropagationFunction aLOSRadarPropagationFunction, double aFixedHeightAboveEllipsoid) Creates a propagation function which computes the visibility of points at a fixed height from a given point.
TLcdLOSPropagationFunctionFixedHeight(ILcdLOSRadarPropagationFunction aLOSRadarPropagationFunction, double aFixedHeight, TLcdCoverageAltitudeMode aFixedHeightMode) Creates a propagation function which computes the visibility of points at a fixed height from a given point.
TLcdLOSPropagationFunctionFixedHeight(ILcdLOSRadarPropagationFunction aLOSRadarPropagationFunction, double aFixedHeight, TLcdCoverageAltitudeMode aFixedHeightMode, TLcdLOSOptions aLOSOption) Creates a propagation function which computes the visibility of points at a fixed height from a given point.

Method Summary

Modifier and Type	Method and Description
void	applyForAzimuthSFCT(double aAzimuth, ILcdLOSCoverageMatrix aLOSCoverageMatrixSFCT) Computes the visibility of points at a fixed height from the center point of a line-of-sight coverage for a given azimuth and stores the resulting values in the line-of-sight coverage matrix.
ILcdLOSCoverageMatrix	createLOSCoverageMatrix(ILcdLOSCoverage aLOSCoverage, ILcdGeoReference aMatrixReference) Creates a coverage matrix using the line-of-sight coverage aLOSCoverage and the matrix reference aMatrixReference.
void	initialize(ILcdLOSCoverage aLOSCoverage, ILcdGeoReference aMatrixReference) Initialize the propagation function with the given coverage aLOSCoverage and the given matrix reference aMatrixReference.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INVISIBLE

public static final int INVISIBLE

The resulting value for points where the object is invisible due to the obstruction of the terrain. For example when a point lies behind a hill or in a valley.

See Also:

Constant Field Values

UNKNOWN

public static final int UNKNOWN

The resulting value for points where the visibility is unknown. For example when no elevation data or invalid data was found at that point.

See Also:

Constant Field Values

CONE_OF_SILENCE

public static final int CONE_OF_SILENCE

The resulting value for the points corresponding to the cone of silence around the given point. This value is used for points which become visible if the vertical angle of the radar is set to [0, 180].

See Also:

Constant Field Values

VISIBLE

public static final int VISIBLE

The resulting value for points where the object is visible.

See Also:

Constant Field Values

Constructor Detail

TLcdLOSPropagationFunctionFixedHeight

public TLcdLOSPropagationFunctionFixedHeight(ILcdLOSRadarPropagationFunction aLOSRadarPropagationFunction,
                                             double aFixedHeightAboveEllipsoid)

Creates a propagation function which computes the visibility of points at a fixed height from a given point. Note that the propagation function cannot be set to null. If this condition is not met, a NullPointerException will be thrown.

Parameters:

aLOSRadarPropagationFunction - The propagation function on which to base its computations.

aFixedHeightAboveEllipsoid - The fixed height value defined in meters above ellipsoid.

Throws:

NullPointerException - when the argument aLOSRadarPropagationFunction is null.

IllegalArgumentException - if the argument aLOSRadarPropagationFunction does not use the mode TLcdEarthRepresentationMode.SPHERICAL_FIXED_RADIUS or TLcdEarthRepresentationMode.SPHERICAL_EULER_RADIUS and if it uses the altitude mode TLcdCoverageAltitudeMode.ABOVE_OBJECT.

TLcdLOSPropagationFunctionFixedHeight

public TLcdLOSPropagationFunctionFixedHeight(ILcdLOSRadarPropagationFunction aLOSRadarPropagationFunction,
                                             double aFixedHeight,
                                             TLcdCoverageAltitudeMode aFixedHeightMode)

Creates a propagation function which computes the visibility of points at a fixed height from a given point. Note that the propagation function cannot be set to null. If this condition is not met, a NullPointerException will be thrown.

Parameters:

aLOSRadarPropagationFunction - The propagation function on which to base its computations.

aFixedHeight - The fixed height value.

aFixedHeightMode - The altitude mode indicating how to interpret the fixed height.

Throws:

NullPointerException - when the argument aLOSRadarPropagationFunction is null.

IllegalArgumentException - if the argument aLOSRadarPropagationFunction does not use the mode TLcdEarthRepresentationMode.SPHERICAL_FIXED_RADIUS or TLcdEarthRepresentationMode.SPHERICAL_EULER_RADIUS, if it uses the altitude mode TLcdCoverageAltitudeMode.ABOVE_OBJECT and if the argument aFixedHeight is set to TLcdCoverageAltitudeMode.ABOVE_OBJECT.

TLcdLOSPropagationFunctionFixedHeight

public TLcdLOSPropagationFunctionFixedHeight(ILcdLOSRadarPropagationFunction aLOSRadarPropagationFunction,
                                             double aFixedHeight,
                                             TLcdCoverageAltitudeMode aFixedHeightMode,
                                             TLcdLOSOptions aLOSOption)

Creates a propagation function which computes the visibility of points at a fixed height from a given point. Note that the propagation function cannot be set to null. If this condition is not met, a NullPointerException will be thrown.

Parameters:

aLOSRadarPropagationFunction - The propagation function on which to base its computations.

aFixedHeight - The fixed height value.

aFixedHeightMode - The altitude mode indicating how to interpret the fixed height.

aLOSOption - A LOS option object containing parameters for the internals of this propagation function and its resulting coverages

Throws:

NullPointerException - when the argument aLOSRadarPropagationFunction is null.

IllegalArgumentException - if the argument aLOSRadarPropagationFunction does not use the mode TLcdEarthRepresentationMode.SPHERICAL_FIXED_RADIUS or TLcdEarthRepresentationMode.SPHERICAL_EULER_RADIUS, if it uses the altitude mode TLcdCoverageAltitudeMode.ABOVE_OBJECT and if the argument aFixedHeight is set to TLcdCoverageAltitudeMode.ABOVE_OBJECT.

Method Detail

createLOSCoverageMatrix

public ILcdLOSCoverageMatrix createLOSCoverageMatrix(ILcdLOSCoverage aLOSCoverage,
                                                     ILcdGeoReference aMatrixReference)

Description copied from interface: ILcdLOSPropagationFunction

Creates a coverage matrix using the line-of-sight coverage aLOSCoverage and the matrix reference aMatrixReference. The result of this method is used as input parameter for the method applyForAzimuthSFCT, which will store the actual matrix values. The matrix should be consistent with the given coverage. This means that all matrix rows and columns represent evenly spaced radii and azimuths as defined by the radial and angular step sizes of the line-of-sight coverage.

The method ILcdLOSPropagationFunction.initialize(com.luciad.tea.ILcdLOSCoverage, com.luciad.reference.ILcdGeoReference) is called with the same arguments as supplied with this method.

The ILcdLOSCoverageMatrix created by this method is guaranteed to be capable of determining its own associatedPointX and associatedPointY properties. These values are not calculated by this ILcdPropagationFunction . An ILcdLOSPropagationFunction does not modify the values of the associatedPointX and associatedPointY for its created ILcdLOSCoverageMatrix.

Specified by:

createLOSCoverageMatrix in interface ILcdLOSPropagationFunction

Parameters:

aLOSCoverage - The covered area and the intermediate step sizes.

aMatrixReference - The reference in which this matrix is defined.

Returns:

the created coverage matrix.

initialize

public void initialize(ILcdLOSCoverage aLOSCoverage,
                       ILcdGeoReference aMatrixReference)

Description copied from interface: ILcdLOSPropagationFunction

Initialize the propagation function with the given coverage aLOSCoverage and the given matrix reference aMatrixReference. For performance reasons, it is recommended that this method initializes all fields that are common to all computations or which do not depend on a specific azimuth.

Specified by:

initialize in interface ILcdLOSPropagationFunction

Parameters:

aLOSCoverage - The covered area to use.

aMatrixReference - The matrix reference in which to compute the matrix values.

applyForAzimuthSFCT

public void applyForAzimuthSFCT(double aAzimuth,
                                ILcdLOSCoverageMatrix aLOSCoverageMatrixSFCT)

Computes the visibility of points at a fixed height from the center point of a line-of-sight coverage for a given azimuth and stores the resulting values in the line-of-sight coverage matrix.

Note that this implementation assumes that the default value of a matrix entry corresponds to the value for invisible points (which is INVISIBLE). Refer to the class documentation for more information about the different visibility values used in this propagation function.

Specified by:

applyForAzimuthSFCT in interface ILcdLOSPropagationFunction

Parameters:

aAzimuth - The azimuth in degrees.

aLOSCoverageMatrixSFCT - The coverage matrix to update.

Throws:

NullPointerException - if the aLOSCoverageMatrixSFCT is null.