org.geotoolkit.referencing.operation.projection
Class ObliqueStereographic

Object
  FormattableObject
      AbstractMathTransform
          AbstractMathTransform2D
              UnitaryProjection
                  Stereographic
                      ObliqueStereographic

All Implemented Interfaces:

Serializable, Formattable, Parameterized, LenientComparable, MathTransform, MathTransform2D

@Immutable
public class ObliqueStereographic
extends Stereographic

Oblique Stereographic projection (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.
  Relevant 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 Guidance 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

Version:

3.20

Author:

Gerald Evenden (USGS), Rueben Schulz (UBC), Martin Desruisseaux (Geomatys), Rémi Maréchal (Geomatys)

See Also:

PolarStereographic, EquatorialStereographic, Serialized Form

Module:

referencing/geotk-referencing (download)

View source code for this class

Nested Class Summary

Nested classes/interfaces inherited from class UnitaryProjection

UnitaryProjection.Parameters

Field Summary

Fields inherited from class UnitaryProjection

excentricity, excentricitySquared

Fields inherited from class FormattableObject

EPSG, GEOTIFF, INTERNAL, OGC, SINGLE_LINE

Constructor Summary

protected

ObliqueStereographic(UnitaryProjection.Parameters parameters) Constructs an oblique stereographic projection (EPSG equations).

Method Summary

protected void	inverseTransform(double[] srcPts, int srcOff, double[] dstPts, int dstOff) Transforms the specified (x,y) coordinates and stores the result in dstPts (angles in radians).
Matrix	transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, boolean derivate) Converts the specified (λ,φ) coordinate (units in radians) and stores the result in dstPts (linear distance on a unit sphere).

Methods inherited from class Stereographic

create, equals

Methods inherited from class UnitaryProjection

computeHashCode, finish, getParameterValues, getUnmarshalledParameters, inverse, resetWarnings, rollLongitude, unrollLongitude

Methods inherited from class AbstractMathTransform2D

getParameterDescriptors, getSourceDimensions, getTargetDimensions, transform

Methods inherited from class AbstractMathTransform

createTransformedShape, derivative, derivative, ensureNonNull, equals, formatWKT, getName, hashCode, isIdentity, rollLongitude, transform, transform, transform, transform, transform

Methods inherited from class FormattableObject

getDefaultIndentation, print, setDefaultIndentation, toString, toWKT, toWKT, toWKT, toWKT

Methods inherited from class Object

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

Methods inherited from interface MathTransform2D

createTransformedShape, derivative

Methods inherited from interface MathTransform

derivative, isIdentity, toWKT, transform, transform, transform, transform, transform

Constructor Detail

ObliqueStereographic

protected ObliqueStereographic(UnitaryProjection.Parameters parameters)

Constructs an oblique stereographic projection (EPSG equations).

Parameters:

parameters - The parameters of the projection to be created.

Method Detail

transform

public Matrix transform(double[] srcPts,
                        int srcOff,
                        double[] dstPts,
                        int dstOff,
                        boolean derivate)
                 throws ProjectionException

Converts the specified (λ,φ) coordinate (units in radians) and stores the result in dstPts (linear distance on a unit sphere). In addition, opportunistically computes the projection derivative if derivate is true.

Overrides:

transform in class Stereographic

Parameters:

srcPts - The array containing the source point coordinate, as (longitude, latitude) angles in radians.

srcOff - The offset of the point to be converted in the source array.

dstPts - The array into which the converted point coordinate is returned (may be the same than srcPts). Ordinates will be expressed in a dimensionless unit, as a linear distance on a unit sphere or ellipse.

dstOff - The offset of the location of the converted point that is stored in the destination array.

derivate - true for computing the derivative, or false if not needed.

Returns:

The matrix of the projection derivative at the given source position, or null if the derivate argument is false.

Throws:

ProjectionException - if the point can't be converted.

Since:

3.20 (derived from 3.00)

See Also:

AbstractMathTransform.derivative(DirectPosition), AbstractMathTransform.transform(DirectPosition, DirectPosition), MathTransforms.derivativeAndTransform(MathTransform, double[], int, double[], int)

inverseTransform

protected void inverseTransform(double[] srcPts,
                                int srcOff,
                                double[] dstPts,
                                int dstOff)
                         throws ProjectionException

Transforms the specified (x,y) coordinates and stores the result in dstPts (angles in radians).

Overrides:

inverseTransform in class Stereographic

Parameters:

srcPts - The array containing the source point coordinate, as linear distance on a unit sphere or ellipse.

srcOff - The offset of the point to be converted in the source array.

dstPts - the array into which the converted point coordinate is returned (may be the same than srcPts). Ordinates will be (longitude, latitude) angles in radians.

dstOff - The offset of the location of the converted point that is stored in the destination array.

Throws:

ProjectionException - if the point can't be converted.