Package org.geotools.referencing.operation.projection

Class ObliqueStereographic

Object

Formattable

AbstractMathTransform

MapProjection

Stereographic

ObliqueStereographic

All Implemented Interfaces:

Serializable, MathTransform, MathTransform2D

public class ObliqueStereographic
extends Stereographic

Provides the transform equations for the Oblique Stereographic (EPSG code 9809). The formulas used below are not from the EPSG, but rather those of the "Oblique Stereographic Alternative" in the libproj4 package written by Gerald Evenden. His work is acknowledged here and greatly appreciated.

The forward equations used in libproj4 are the same as those given in the UNB reports for the Double Stereographic. The inverse equations are similar, but use different methods to iterate for the latitude.

References:

• libproj4 is available at libproj4 Miscellanea
  Relevent files are: PJ_sterea.c, pj_gauss.c, pj_fwd.c, pj_inv.c and lib_proj.h
• Gerald Evenden. "Supplementary PROJ.4 Notes - Oblique Stereographic Alternative"
• "Coordinate Conversions and Transformations including Formulas", EPSG Guidence Note Number 7, Version 19.
• Krakiwsky, E.J., D.B. Thomson, and R.R. Steeves. 1977. A Manual For Geodetic Coordinate Transformations in the Maritimes. Geodesy and Geomatics Engineering, UNB. Technical Report No. 48.
• Thomson, D.B., M.P. Mepham and R.R. Steeves. 1977. The Stereographic Double Projection. Surveying Engineering, University of New Brunswick. Technical Report No. 46.

Since:

2.4

Author:

Gerald I. Evenden (for original code in Proj4), Rueben Schulz

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ObliqueStereographic.Provider	The math transform provider for a stereographic projection of any kind.

Nested classes/interfaces inherited from class MapProjection

MapProjection.AbstractProvider

Field Summary

Fields inherited from class MapProjection

centralMeridian, en0, en1, en2, en3, en4, excentricity, excentricitySquared, falseEasting, falseNorthing, globalScale, invertible, isSpherical, latitudeOfOrigin, LOGGER, scaleFactor, semiMajor, semiMinor, SKIP_SANITY_CHECKS

Fields inherited from class Formattable

SINGLE_LINE

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ObliqueStereographic(ParameterValueGroup parameters)	Constructs an oblique stereographic projection (EPSG equations).

Method Summary

Modifier and Type	Method	Description
protected double	getToleranceForAssertions(double longitude, double latitude)	Maximal error (in metres) tolerated for assertions, if enabled.
protected Point2D	inverseTransformNormalized(double x, double y, Point2D ptDst)	Transforms the specified (x,y) coordinates and stores the result in ptDst.
protected Point2D	transformNormalized(double x, double y, Point2D ptDst)	Transforms the specified (λ,φ) coordinates (units in radians) and stores the result in ptDst (linear distance on a unit sphere).

Methods inherited from class Stereographic

equals, getParameterDescriptors, hashCode

Methods inherited from class MapProjection

checkReciprocal, getParameterValues, getSourceDimensions, getTargetDimensions, inv_mlfn, inverse, mlfn, orthodromicDistance, resetWarnings, transform, transform, transform

Methods inherited from class AbstractMathTransform

createTransformedShape, derivative, derivative, ensureNonNull, formatWKT, getName, isIdentity, needCopy, normalizeAngle, rollLongitude, transform, transform, transform

Methods inherited from class Formattable

cleanupThreadLocals, toString, toWKT, toWKT, toWKT, toWKT

Methods inherited from class Object

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

Methods inherited from interface MathTransform

derivative, isIdentity, toWKT, transform, transform, transform

Methods inherited from interface MathTransform2D

createTransformedShape, derivative

Constructor Detail

ObliqueStereographic

protected ObliqueStereographic(ParameterValueGroup parameters)
                        throws ParameterNotFoundException

Constructs an oblique stereographic projection (EPSG equations).

Parameters:

parameters - The group of parameter values.

Throws:

ParameterNotFoundException - if a required parameter was not found.

Method Detail

transformNormalized

protected Point2D transformNormalized(double x,
                                      double y,
                                      Point2D ptDst)
                               throws ProjectionException

Transforms the specified (λ,φ) coordinates (units in radians) and stores the result in ptDst (linear distance on a unit sphere).

Parameters:

x - The longitude of the coordinate, in radians.

y - The latitude of the coordinate, in radians.

ptDst - the specified coordinate point that stores the result of transforming ptSrc, or null. Ordinates will be in a dimensionless unit, as a linear distance on a unit sphere or ellipse.

Returns:

the coordinate point after transforming (lambda, phi) and storing the result in ptDst.

Throws:

ProjectionException - if the point can't be transformed.

inverseTransformNormalized

protected Point2D inverseTransformNormalized(double x,
                                             double y,
                                             Point2D ptDst)
                                      throws ProjectionException

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

Parameters:

x - The easting of the coordinate, linear distance on a unit sphere or ellipse.

y - The northing of the coordinate, linear distance on a unit sphere or ellipse.

ptDst - the specified coordinate point that stores the result of transforming ptSrc, or null. Ordinates will be in radians.

Returns:

the coordinate point after transforming x, y and storing the result in ptDst.

Throws:

ProjectionException - if the point can't be transformed.

getToleranceForAssertions

protected double getToleranceForAssertions(double longitude,
                                           double latitude)

Maximal error (in metres) tolerated for assertions, if enabled.

Overrides:

getToleranceForAssertions in class MapProjection

Parameters:

longitude - The longitude in decimal degrees.

latitude - The latitude in decimal degrees.

Returns:

The tolerance level for assertions, in meters.