com.ctreber.acearth.projection
Class Projection

java.lang.Object
  com.ctreber.acearth.projection.Projection

Direct Known Subclasses:

ProjectionCyl, ProjectionMerc, ProjectionOrtho

public abstract class Projection
extends Object

A projection for a globe on a flat surface (must be subclassed).

© 2002 Christian Treber, [email protected]

Author:

Christian Treber, [email protected]

Constructor Summary

Projection()

Method Summary

Point2D	finalize(Point2D pPoint)
double	finalizeX(double pX) Since the final mapping is relative to the center of the image -PI and PI get mapped to the left and right border respectively.
double	finalizeY(double pY) Since the final mapping is relative to the center of the image -PI and PI get mapped to the bottom and top border respectively.
abstract Coordinate	getLocation(int pX, int pY) Translate screen point into coordinate on Earth.
double	getScale()
Coordinate	getViewPos()
void	initTransformTable() Initialize transform parameters, set offset to center of image (plus shifts), set scale
double	inverseFinalizeX(double x) Transform screen to image coordinates.
double	inverseFinalizeY(double y) Transform screen to image coordinates.
abstract double	inverseProjectX(double pX)
abstract double	inverseProjectY(double pY)
abstract boolean	isVisible(Point3D pPoint)
boolean	isWithinImage(Point2D pPoint)
Point2D	project2D(Point3D pPoint) Imagine view the globe, N is up, S is down, and N0E0 is in the center.
protected abstract double	projectX(double pX, double pZ) Project 3D point on x axis.
abstract double	projectY(double pY) Project 3D point on y axis.
Point3D	rotate(Point3D pPoint) Rotate the point according to the current rotation of Earth.
Point3D	rotateReverse(Point3D pPoint)
void	setImageHeight(int pImageHeight)
void	setImageWidth(int pImageWidth)
protected abstract void	setScale()
void	setShiftX(int pX)
void	setShiftY(int pY)
void	setViewMagnification(double pViewMagnification)
void	setViewPos(Coordinate pViewPos)
void	setViewRotation(double pViewRotation)

Methods inherited from class java.lang.Object

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

Constructor Detail

Projection

public Projection()

Method Detail

initTransformTable

public void initTransformTable()

Initialize transform parameters, set offset to center of image (plus shifts), set scale

setScale

protected abstract void setScale()

projectY

public abstract double projectY(double pY)

Project 3D point on y axis.

inverseProjectY

public abstract double inverseProjectY(double pY)

projectX

protected abstract double projectX(double pX,
                                   double pZ)

Project 3D point on x axis.

inverseProjectX

public abstract double inverseProjectX(double pX)

isVisible

public abstract boolean isVisible(Point3D pPoint)

isWithinImage

public boolean isWithinImage(Point2D pPoint)

getLocation

public abstract Coordinate getLocation(int pX,
                                       int pY)

Translate screen point into coordinate on Earth.

Parameters:

pX -

pY -

Returns:

project2D

public Point2D project2D(Point3D pPoint)

Imagine view the globe, N is up, S is down, and N0E0 is in the center. x is right/left, y is up/down, and z is front/rear.

Map points are located on the surface of a unit sphere (diameter = 1). Latitude is the angle between x and y or z and y. Longitude is the angle between x and z.

Why? The way we choose our global coordinate system, longitude circles (latidude variable) always have the same size while the size of latidude circles (longitude variable) depends on the latitude.

Parameters:

pPoint -

Returns:

finalize

public Point2D finalize(Point2D pPoint)

finalizeX

public double finalizeX(double pX)

Since the final mapping is relative to the center of the image -PI and PI get mapped to the left and right border respectively. But see ProjectionOrtho.setScale().

finalizeY

public double finalizeY(double pY)

Since the final mapping is relative to the center of the image -PI and PI get mapped to the bottom and top border respectively. But see ProjectionOrtho.setScale().

inverseFinalizeX

public double inverseFinalizeX(double x)

Transform screen to image coordinates.

inverseFinalizeY

public double inverseFinalizeY(double y)

Transform screen to image coordinates.

rotate

public Point3D rotate(Point3D pPoint)

Rotate the point according to the current rotation of Earth.

rotateReverse

public Point3D rotateReverse(Point3D pPoint)

getScale

public double getScale()

getViewPos

public Coordinate getViewPos()

setViewMagnification

public void setViewMagnification(double pViewMagnification)

setViewPos

public void setViewPos(Coordinate pViewPos)

setShiftX

public void setShiftX(int pX)

setShiftY

public void setShiftY(int pY)

setViewRotation

public void setViewRotation(double pViewRotation)

setImageWidth

public void setImageWidth(int pImageWidth)

setImageHeight

public void setImageHeight(int pImageHeight)