mil.navy.nps.rra

Class Bottom

java.lang.Object

mil.navy.nps.rra.Bottom

public class Bottom
extends Object

Simulates the acoustic characteristics of reflection, absorption and geometry for the ocean bottom. Currently only a rigid bottom is modeled.

Since a ray is the normal vector to a plane wave, rays interact with surfaces the same way that plane waves do. Rays obey Snell's law and the equations of reflection and transmission of wave energy. This model uses vector algebra to determine when the end of a ray has passed through the bottom and to reflect any rays that have penetrated.

Beams of energy can be considered to consist of bundles of sound rays. The energy in a bundle can be shown not to diverge from the bundle. Thus the energy in a bundle is constant, and subsequently the product of the intensity versus the area of the bundle perpendicular to direction of propagation is a constant as well. Therefore a beam is a fundamental building block for constructing a multiple-beam Lobe of a sonar pattern.

Version:

$Revision: 1.11 $

Author:

LT Timothy M. Holliday USN

Contact: Don Brutzman (web.nps.navy.mil/~brutzman) brutzman@nps.navy.mil

Source Code:

http://web.nps.navy.mil/~brutzman/vrtp/mil/navy/nps/rra/Bottom.java

History:

8 November 97	Timothy M. Holliday	New
18 March 98	Timothy M. Holliday	Added HTML comment convention
16 October 98	Don Brutzman	Javadoc updates for jdk1.2b4
25 April 99	Don Brutzman	Javadoc updates for jdk1.2.1, revised some method names to match get/set naming convention.

Reference:

Holliday, Timothy, Real-Time 3D Sonar Modeling and Visualization, Master's Thesis, Naval Postgraduate School, Monterey California, June 1998. Available at web.nps.navy.mil/~brutzman/vrtp/rra/HollidayRRAthesis.pdf. Slideset available in Powerpoint and Acrobat .pdf formats.

See Also:

Surface

Constructor Summary

Constructors

Constructor and Description
Bottom(Bathymetry bathValues, double size, double spacing) Constructs Bottom object giving bath values, size, and spacing.

Method Summary

Modifier and Type	Method and Description
double	depth(double x, double z) This method returns the bottom depth at the given (x,z) coordinate (expressed in the Ziomek Coordinate System).
String	generateColorScheme(double[] array) This method generates the color scheme.
static boolean	getAppendLineFeed() This is a static method that returns the current line appendage.
double[]	getLocalDepths(Vec3d pos) This method gets the local depths.
double	getMinDepth() This method returns the maximum or minimum depth.
double	getTranslation() This method returns translation.
String	getVRMLBottom() This method returns the VRML string representing the bottom of the ocean.
double	interpolateCurrentDepth(double[] localDepths) Pos is in meters from NE point of column
double	reflect(Vec3d Pos, Vec3d normal, double curDepth) This method causes a Snell's Law reflection to occur.
static void	setAppendLineFeed(boolean pAppendLineFeed) This is a static method used to indicate whether a line feed is desired at the end of every line.
String	VRMLScales() This method applies scales to the VRML bottom for the x, y and z directions.

Methods inherited from class java.lang.Object

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

Constructor Detail

Bottom

public Bottom(Bathymetry bathValues,
              double size,
              double spacing)

Constructs Bottom object giving bath values, size, and spacing.

Parameters:

bathValues - The array of bathymetric values (in meters).

size - The size of area.

spacing - The size of spacing.

Method Detail

getMinDepth

public double getMinDepth()

This method returns the maximum or minimum depth.

Returns:

the maximum or minimum depth.

getTranslation

public double getTranslation()

This method returns translation.

Returns:

Translate an object along one or more of its three axes.

getLocalDepths

public double[] getLocalDepths(Vec3d pos)

This method gets the local depths.

Parameters:

pos - Three elements of vectors.

Returns:

The results of the array of length and points.

interpolateCurrentDepth

public double interpolateCurrentDepth(double[] localDepths)

Pos is in meters from NE point of column

Parameters:

localDepths - The array of the depths.

Returns:

Interpolation or the result of the calculation of nsDepth or ewDepth.

reflect

public double reflect(Vec3d Pos,
                      Vec3d normal,
                      double curDepth)

This method causes a Snell's Law reflection to occur.

Parameters:

Pos - Vector arithmetic routines for 3-element vectors of type Double.

normal - Vector arithmetic routines for 3-element vectors of type Double.

curDepth - double.

Returns:

0.0.

depth

public double depth(double x,
                    double z)

This method returns the bottom depth at the given (x,z) coordinate (expressed in the Ziomek Coordinate System).

Parameters:

x - The coordinate x.

z - The coordinate z.

Returns:

Interpolate current depth.

getVRMLBottom

public String getVRMLBottom()

This method returns the VRML string representing the bottom of the ocean. Takes into account weirde Xj3D bug that requires stretching of watercolumn to fit terrain (point + 1)/points

Returns:

VRML string.

generateColorScheme

public String generateColorScheme(double[] array)

This method generates the color scheme.

Parameters:

array - The array of bathymetric values (in meters)

Returns:

String of value of color.

VRMLScales

public String VRMLScales()

This method applies scales to the VRML bottom for the x, y and z directions.

Returns:

VRML string for the in-scene spatial scale.

setAppendLineFeed

public static void setAppendLineFeed(boolean pAppendLineFeed)

This is a static method used to indicate whether a line feed is desired at the end of every line.

Parameters:

pAppendLineFeed - 'true' indicates a linefeed is desired and 'false' indicates that a space is desired"

getAppendLineFeed

public static boolean getAppendLineFeed()

This is a static method that returns the current line appendage.

Returns:

'true' indicates a linefeed is desired and 'false' indicates that a space is desired"