jview
Class CylindricalProjection

java.lang.Object
  jview.AbstractFormattingTransform
      jview.CylindricalProjection

All Implemented Interfaces:

CoordinateTransforming, DeltaFormattedTransforming, DeltaTransforming, FormattedTransforming

Direct Known Subclasses:

CylindricalEqualAreaProjection, CylindricalEquidistantProjection, MercatorProjection

public class CylindricalProjection
extends AbstractFormattingTransform

Base class for cylindrical projections of geographic coordinates longitude λ and latitude φ, both measured in degrees. Longitudes to the east are positive. From a central meridian, λ_0 , and a k_0, you get to NormalizedCoordinates via.

   x = confine360(λ-λ_0+180.)/360.
   y = 0.5-k_0*tan(φ), |φ| < atan(1/2k_0) 
   

The name is kept also for non-straight cylindrical projections, that change the y-dependency.
Each cylindrical projection should provide a default constructor and a constructor with a single double, the central meridian.

Field Summary

private double	k0 The k0 factor for phi scaling.
protected double	lambda0 The central meridian.
private boolean	sexagesimal If true, we use sexagesimal format.
static double	TOPLATITUDE The default highest latitude to show.

Constructor Summary

	CylindricalProjection() Constructs a new cylindrical Projection for the greenwhich standard.
	CylindricalProjection(double l0) Constructs a new cylindrical Projection for the given standard, scaling such that all up to TOPLATITUDE is visible.
protected	CylindricalProjection(double l0, double k) Constructs a cylindrical Projection with the given central meridian and a scaling factor for y.

Method Summary

protected Format	deduceFormat(double degrees) Returns a format that is decued from the viewing size.
Format	estimateX(double xs) Estimates the decimal formatter to use on the axis.
Format	estimateY(double xs) Estimates the decimal formatter to use on the axis.
protected double	getLambda(Point2D norm) The standard cylindrical projection uses
protected double	getPhi(Point2D norm) This method is normally overriddn, as cylindric projection is a general term used for other projection with the same x, but different y transformation.
protected double	getScale() Returns the scaling factor.
protected double	getX(VectorG lamphi) The standard cylindrical projection uses
protected double	getY(VectorG lamphi) This method is normally overriddn, as cylindric projection is a general term used for other projection with the same x, but different y transformation.
void	setSexagesimal(boolean sex) Sets the sexagesimal scale in the format.
Point2D	toNormalizedDistance(VectorG location, VectorG delta) We call the #toNormalized twice and return the difference.
Point2D	toNormalizedSpace(VectorG lamphi) Converts user space corrdinates, which are a longitude/latitude pair in degrees into x/y.
VectorG	toUserDistance(Rectangle2D norm) We call the toUserSpace(java.awt.geom.Point2D) twice and return the difference.
VectorG	toUserSpace(Point2D pix) Converts normalized space into user space.

Methods inherited from class jview.AbstractFormattingTransform

deltaFormatUserSpaceX, deltaFormatUserSpaceY, formatUserCoordinates, formatUserSpaceX, formatUserSpaceY, getFormatUserX, getFormatUserY, setDeltaFormatUserX, setDeltaFormatUserY, setFormatUserX, setFormatUserY, useEstimatedFormats

Methods inherited from class java.lang.Object

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

Field Detail

TOPLATITUDE

public static final double TOPLATITUDE

The default highest latitude to show.

See Also:

Constant Field Values

lambda0

protected double lambda0

The central meridian.

k0

private double k0

The k0 factor for phi scaling.

sexagesimal

private boolean sexagesimal

If true, we use sexagesimal format.

Constructor Detail

CylindricalProjection

public CylindricalProjection()

Constructs a new cylindrical Projection for the greenwhich standard.

CylindricalProjection

public CylindricalProjection(double l0)

Constructs a new cylindrical Projection for the given standard, scaling such that all up to TOPLATITUDE is visible.

CylindricalProjection

protected CylindricalProjection(double l0,
                                double k)

Constructs a cylindrical Projection with the given central meridian and a scaling factor for y.

Method Detail

getScale

protected double getScale()

Returns the scaling factor.

toNormalizedSpace

public Point2D toNormalizedSpace(VectorG lamphi)

Converts user space corrdinates, which are a longitude/latitude pair in degrees into x/y. Lambda is positve to the east.

Parameters:

lamphi - A vector of user coordinates.

Returns:

A point in normalized screen coordinate, with 0≤x,y≤1

toUserSpace

public VectorG toUserSpace(Point2D pix)

Converts normalized space into user space.

Parameters:

pix - A pixel in normalized coordinates.

Returns:

A vector in user space, never null

getX

protected double getX(VectorG lamphi)

The standard cylindrical projection uses

       x = confine360(λ-λ_0+180.)/360.
       

getY

protected double getY(VectorG lamphi)

This method is normally overriddn, as cylindric projection is a general term used for other projection with the same x, but different y transformation. The standard cylindrcal projection uses

       y = 0.5-k_0*tan(φ), |φ| < atan(1/2k_0) 
       

getLambda

protected double getLambda(Point2D norm)

The standard cylindrical projection uses

       λ=confine360(360*x+λ_0)-180.
       

getPhi

protected double getPhi(Point2D norm)

This method is normally overriddn, as cylindric projection is a general term used for other projection with the same x, but different y transformation. The standard cylindrcal projection uses

       φ = atan((0.5-y)/k_0)
       

toNormalizedDistance

public Point2D toNormalizedDistance(VectorG location,
                                    VectorG delta)

We call the #toNormalized twice and return the difference.

toUserDistance

public VectorG toUserDistance(Rectangle2D norm)

We call the toUserSpace(java.awt.geom.Point2D) twice and return the difference.

estimateX

public Format estimateX(double xs)

Estimates the decimal formatter to use on the axis.

estimateY

public Format estimateY(double xs)

Estimates the decimal formatter to use on the axis.

setSexagesimal

public void setSexagesimal(boolean sex)

Sets the sexagesimal scale in the format.

deduceFormat

protected Format deduceFormat(double degrees)

Returns a format that is decued from the viewing size. If distance is smaller than 1 arcmin, we always use scientific notation.