Class ObliqueStereographic

All Implemented Interfaces:
Serializable, Parameterized, Lenient­Comparable, Math­Transform, Math­Transform2D

public class ObliqueStereographic extends NormalizedProjection
Oblique Stereographic projection (EPSG code 9809). See the following references for an overview:

Description

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 frequently used for mapping polar areas, but can also be used for other limited areas centered on a point.

This projection involves two steps: first a conversion of geodetic coordinates to conformal coordinates (i.e. latitudes and longitudes on a conformal sphere), then a spherical stereographic projection. For this reason this projection method is sometime known as "Double Stereographic".

Note: there is another method known as "Oblique Stereographic Alternative" or sometime just "Stereographic". That alternative uses a simplified conversion computing the conformal latitude of each point on the ellipsoid. Both methods are considered valid but produce slightly different results. For this reason EPSG considers them as different projection methods.
Since:
0.7
See Also:

Defined in the sis-referencing module

  • Constructor Details

    • ObliqueStereographic

      public ObliqueStereographic(OperationMethod method, Parameters parameters)
      Creates an Oblique Stereographic projection from the given parameters. The method argument can be the description of one of the following:
      • "Oblique Stereographic", also known as "Roussilhe".
      Parameters:
      method - description of the projection parameters.
      parameters - the parameter values of the projection to create.
  • Method Details

    • createMapProjection

      public MathTransform createMapProjection(MathTransformFactory factory) throws FactoryException
      Returns the sequence of normalizationthisdenormalization transforms as a whole. The transform returned by this method expects (longitude, latitude) coordinates in degrees and returns (x,y) coordinates in metres.

      The non-linear part of the returned transform will be this transform, except if the ellipsoid is spherical. In the later case, this transform will be replaced by a simplified implementation.

      Overrides:
      create­Map­Projection in class Normalized­Projection
      Parameters:
      factory - the factory to use for creating the transform.
      Returns:
      the map projection from (λ,φ) to (x,y) coordinates.
      Throws:
      Factory­Exception - if an error occurred while creating a transform.
      See Also:
    • 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. In addition, opportunistically computes the projection derivative if derivate is true.
      Specified by:
      transform in class Normalized­Projection
      Parameters:
      src­Pts - the array containing the source point coordinate, as (longitude, latitude) angles in radians.
      src­Off - the offset of the single coordinate to be converted in the source array.
      dst­Pts - the array into which the converted coordinate is returned (may be the same than src­Pts). Coordinates 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 coordinate 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 coordinate can not be converted.
      See Also:
    • inverseTransform

      protected void inverseTransform(double[] srcPts, int srcOff, double[] dstPts, int dstOff) throws ProjectionException
      Converts the specified (x,y) coordinates and stores the result in dst­Pts (angles in radians).
      Specified by:
      inverse­Transform in class Normalized­Projection
      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). Coordinates 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 not be converted.