org.geotools.ct.proj
Class Stereographic

java.lang.Object
  org.geotools.ct.AbstractMathTransform
      org.geotools.ct.proj.MapProjection
          org.geotools.ct.proj.PlanarProjection
              org.geotools.ct.proj.Stereographic

All Implemented Interfaces:

MathTransform, MathTransform2D, java.io.Serializable

Direct Known Subclasses:

ObliqueStereographic, PolarStereographic

Deprecated. Replaced by Stereographic.

public abstract class Stereographic

extends PlanarProjection

Stereographic Projection. The directions starting from the central point are true, but the areas and the lengths become increasingly deformed as one moves away from the center. This projection is used to represent polar areas. It can be adapted for other areas having a circular form.

This implementation, and its subclasses, provides transforms for four cases of the stereographic projection:

• "Oblique_Stereographic" (EPSG code 9809), alias "Double Stereographic" in ESRI software
• "Stereographic" in ESRI software (NOT EPSG code 9809)
• "Polar_Stereographic" (EPSG code 9810, uses iteration for the inverse)
• "Polar_Stereographic_Series" (EPSG code 9810), uses a series for the inverse. This is a little bit faster, but may be a little bit less accurate)

Both the "Oblique_Stereographic" and "Stereographic" projections are "double" projections involving two parts: 1) a conformal transformation of the geographic coordinates to a sphere and 2) a spherical Stereographic projection. The EPSG considers both methods to be valid, but considers them to be a different coordinate operation method.

The "Stereographic" case uses the USGS equations of Snyder. This uses a simplified conversion to the conformal sphere that computes the conformal latitude of each point on the sphere.

The "Oblique_Stereographic" case uses equations from the EPSG. This uses a more generalized form of the conversion to the conformal sphere; using only a single conformal sphere at the origin point. Since this is a "double" projection, it is sometimes called the "Double Stereographic". The "Oblique_Stereographic" is used in New Brunswick (Canada) and the Netherlands.

The "Stereographic" and "Double Stereographic" names are used in ESRI's ArcGIS 8.x product. The "Oblique_Stereographic" name is the EPSG name for the later only.

WARNING: Tests points calculated with ArcGIS's "Double Stereographic" are not always equal to points calculated with the "Oblique_Stereographic". However, where there are differences, two different implementations of these equations (EPSG guidence note 7 and libproj) calculate the same values. Until these differences are resolved, please be careful when using this projection.

If a "latitude_of_origin" parameter is supplied and is not consistent with the projection classification (for example a latitude different from ±90? for the polar case), then the oblique or polar case will be automatically inferred from the latitude. In other words, the latitude of origin has precedence on the projection classification. If ommited, then the default value is 90?N for "Polar_Stereographic" and 0? for "Oblique_Stereographic".

The "latitude_true_scale" parameter is not specified by the EPSG and is only used for the "Polar_Stereographic" case. The "Polar_Stereographic_Series" does not include this parameter. 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.
• Gerald Evenden. "Supplementary PROJ.4 Notes - Oblique Stereographic Alternative"
• 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. Geodesy and Geomatics Engineereng, UNB. Technical Report No. 46.

Version:

$Id: Stereographic.java 17672 2006-01-19 00:25:55Z desruisseaux $

Author:

Andr? Gosselin, Martin Desruisseaux, Rueben Schulz

See Also:

Stereographic projection on MathWorld, Polar_Stereographic, Oblique_Stereographic, Stereographic, Some Random Stereographic Issues, Serialized Form

Task:

TODO: Declares that "Stereographic" is an ESRI name. Add the "Double Stereographic" alias (from ESRI) for "Oblique_Stereographic".

Field Summary

Fields inherited from class org.geotools.ct.proj.MapProjection

centralMeridian, e, es, falseEasting, falseNorthing, globalScale, isSpherical, latitudeOfOrigin, scaleFactor, semiMajor, semiMinor

Fields inherited from interface org.geotools.ct.MathTransform2D

IDENTITY

Constructor Summary

protected

Stereographic(Projection parameters) Deprecated. Construct a stereographic transformation from the specified parameters.

Method Summary

java.lang.String

getName(java.util.Locale locale) Deprecated. Returns a human readable name localized for the specified locale.

Methods inherited from class org.geotools.ct.proj.MapProjection

equals, getDimSource, getDimTarget, hashCode, inverse, inverseTransformNormalized, toString, transform, transform, transform, transformNormalized

Methods inherited from class org.geotools.ct.AbstractMathTransform

createTransformedShape, derivative, derivative, fromGeoAPI, isIdentity, transform

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.geotools.ct.MathTransform2D

createTransformedShape, derivative

Methods inherited from interface org.geotools.ct.MathTransform

derivative, isIdentity, transform

Constructor Detail

Stereographic

protected Stereographic(Projection parameters)
                 throws MissingParameterException

Deprecated.

Construct a stereographic transformation from the specified parameters.

Parameters:

parameters - The parameter values in standard units.

Throws:

MissingParameterException - if a mandatory parameter is missing.

Method Detail

getName

public java.lang.String getName(java.util.Locale locale)

Deprecated.

Returns a human readable name localized for the specified locale.

Specified by:

getName in class MapProjection