org.openstreetmap.josm.data.projection.proj

Class CassiniSoldner

java.lang.Object

org.openstreetmap.josm.data.projection.proj.AbstractProj

org.openstreetmap.josm.data.projection.proj.CassiniSoldner

All Implemented Interfaces:

Proj

public class CassiniSoldner
extends AbstractProj

Cassini-Soldner Projection (EPSG code 9806). The Cassini-Soldner Projection is the ellipsoidal version of the Cassini projection for the sphere. It is not conformal but as it is relatively simple to construct it was extensively used in the last century and is still useful for mapping areas with limited longitudinal extent. It has now largely been replaced by the conformal Transverse Mercator which it resembles. Like this, it has a straight central meridian along which the scale is true, all other meridians and parallels are curved, and the scale distortion increases rapidly with increasing distance from the central meridian.

This class has been derived from the implementation of the Geotools project; git 8cbf52d, org.geotools.referencing.operation.projection.CassiniSoldner at the time of migration.

Field Summary

Fields

Modifier and Type	Field and Description
private static double	C1 Constants used for the forward and inverse transform for the elliptical case of the Cassini-Soldner.
private static double	C2
private static double	C3
private static double	C4
private static double	C5
private double	ml0 Meridian distance at the latitudeOfOrigin.
private double	phi0 Latitude of origin.

Fields inherited from class org.openstreetmap.josm.data.projection.proj.AbstractProj

e, e2, en0, en1, en2, en3, en4, spherical

Constructor Summary

Constructors

Constructor and Description
CassiniSoldner()

Method Summary

Modifier and Type	Method and Description
Bounds	getAlgorithmBounds() Return the bounds where this projection is applicable.
java.lang.String	getName() Replies a human readable name of this projection.
java.lang.String	getProj4Id() Replies the Proj.4 identifier.
void	initialize(ProjParameters params) Initialize the projection using the provided parameters.
double[]	invproject(double x, double y) Convert east/north to lat/lon.
double[]	project(double phi, double lam) Convert lat/lon to east/north.

Methods inherited from class org.openstreetmap.josm.data.projection.proj.AbstractProj

aasin, cphi2, invMlfn, isGeographic, mlfn, msfn, tsfn

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.openstreetmap.josm.data.projection.proj.Proj

lonIsLinearToEast

Field Detail

ml0

private double ml0

Meridian distance at the latitudeOfOrigin. Used for calculations for the ellipsoid.

phi0

private double phi0

Latitude of origin.

C1

private static final double C1

Constants used for the forward and inverse transform for the elliptical case of the Cassini-Soldner.

See Also:

Constant Field Values

C2

private static final double C2

See Also:

Constant Field Values

C3

private static final double C3

See Also:

Constant Field Values

C4

private static final double C4

See Also:

Constant Field Values

C5

private static final double C5

See Also:

Constant Field Values

Constructor Detail

CassiniSoldner

public CassiniSoldner()

Method Detail

getName

public java.lang.String getName()

Description copied from interface: Proj

Replies a human readable name of this projection.

Returns:

The projection name. must not be null.

getProj4Id

public java.lang.String getProj4Id()

Description copied from interface: Proj

Replies the Proj.4 identifier.

Returns:

The Proj.4 identifier (as reported by cs2cs -lp). If no id exists, return null.

initialize

public void initialize(ProjParameters params)
                throws ProjectionConfigurationException

Description copied from interface: Proj

Initialize the projection using the provided parameters.

Specified by:

initialize in interface Proj

Overrides:

initialize in class AbstractProj

Parameters:

params - The projection parameters

Throws:

ProjectionConfigurationException - in case parameters are not suitable

project

public double[] project(double phi,
                        double lam)

Description copied from interface: Proj

Convert lat/lon to east/north.

Parameters:

phi - the latitude in radians

lam - the longitude in radians

Returns:

array of length 2, containing east and north value in meters, divided by the semi major axis of the ellipsoid.

invproject

public double[] invproject(double x,
                           double y)

Description copied from interface: Proj

Convert east/north to lat/lon.

Parameters:

x - east value in meters, divided by the semi major axis of the ellipsoid

y - north value in meters, divided by the semi major axis of the ellipsoid

Returns:

array of length 2, containing lat and lon in radians.

getAlgorithmBounds

public Bounds getAlgorithmBounds()

Description copied from interface: Proj

Return the bounds where this projection is applicable. This is a fallback for when the projection bounds are not specified explicitly. In this area, the round trip lat/lon -> east/north -> lat/lon should return the starting value with small error. In addition, regions with extreme distortions should be excluded, if possible. It need not be the absolute maximum, but rather an area that is safe to display in JOSM and contain everything that one would expect to use.

Returns:

the bounds where this projection is applicable, null if unknown