org.geotools.referencing.operation.projection

Class IdrMercator

java.lang.Object

MapProjection

org.geotools.referencing.operation.projection.IdrMercator

public class IdrMercator
extends MapProjection

Mercator Cylindrical Projection. The parallels and the meridians are straight lines and cross at right angles; this projection thus produces rectangular charts. The scale is true along the equator (by default) or along two parallels equidistant of the equator (if a scale factor other than 1 is used). This projection is used to represent areas close to the equator. It is also often used for maritime navigation because all the straight lines on the chart are loxodrome lines, i.e. a ship following this line would keep a constant azimuth on its compass.

This implementation handles both the 1 and 2 stardard parallel cases. For Mercator_1SP (EPSG code 9804), the line of contact is the equator. For Mercator_2SP (EPSG code 9805) lines of contact are symmetrical about the equator.

References:

• John P. Snyder (Map Projections - A Working Manual,
  U.S. Geological Survey Professional Paper 1395, 1987)
• "Coordinate Conversions and Transformations including Formulas",
  EPSG Guidence Note Number 7, Version 19.

See Also:

Mercator projection on MathWorld, "mercator_1sp" on Remote Sensing, "mercator_2sp" on Remote Sensing

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	IdrMercator.Provider1SP The MathTransformProvider for a IdrMercator 1SP projection.
static class	IdrMercator.Provider2SP The MathTransformProvider for a IdrMercator 2SP projection.

Field Summary

Fields

Modifier and Type	Field and Description
protected double	standardParallel Standard Parallel used for the Mercator_2SP case.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	IdrMercator(ParameterValueGroup parameters) Constructs a new map projection from the supplied parameters.

Method Summary

Modifier and Type	Method and Description
boolean	equals(java.lang.Object object) Compares the specified object with this map projection for equality.
ParameterDescriptorGroup	getParameterDescriptors()
ParameterValueGroup	getParameterValues()
int	hashCode() Returns a hash value for this projection.
protected java.awt.geom.Point2D	inverseTransformNormalized(double x, double y, java.awt.geom.Point2D ptDst) Transforms the specified (x,y) coordinate and stores the result in ptDst.
protected java.awt.geom.Point2D	transformNormalized(double x, double y, java.awt.geom.Point2D ptDst) Transforms the specified (x,y) coordinate (units in radians) and stores the result in ptDst (linear distance on a unit sphere).

Methods inherited from class java.lang.Object

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

Field Detail

standardParallel

protected final double standardParallel

Standard Parallel used for the Mercator_2SP case. Set to Double.NaN for the Mercator_1SP case.

Constructor Detail

IdrMercator

protected IdrMercator(ParameterValueGroup parameters)
               throws ParameterNotFoundException

Constructs a new map projection from the supplied parameters.

Parameters:

parameters - The parameter values in standard units.

Throws:

ParameterNotFoundException - if a mandatory parameter is missing.

Method Detail

getParameterDescriptors

public ParameterDescriptorGroup getParameterDescriptors()

getParameterValues

public ParameterValueGroup getParameterValues()

transformNormalized

protected java.awt.geom.Point2D transformNormalized(double x,
                                                    double y,
                                                    java.awt.geom.Point2D ptDst)
                                             throws ProjectionException

Transforms the specified (x,y) coordinate (units in radians) and stores the result in ptDst (linear distance on a unit sphere).

Throws:

ProjectionException

inverseTransformNormalized

protected java.awt.geom.Point2D inverseTransformNormalized(double x,
                                                           double y,
                                                           java.awt.geom.Point2D ptDst)
                                                    throws ProjectionException

Transforms the specified (x,y) coordinate and stores the result in ptDst.

Throws:

ProjectionException

hashCode

public int hashCode()

Returns a hash value for this projection.

equals

public boolean equals(java.lang.Object object)

Compares the specified object with this map projection for equality.