Package org.apache.sis.referencing.operation.projection

Class ModifiedAzimuthalEquidistant

java.lang.Object
org.apache.sis.io.wkt.FormattableObject
org.apache.sis.referencing.operation.transform.AbstractMathTransform
org.apache.sis.referencing.operation.transform.AbstractMathTransform2D
org.apache.sis.referencing.operation.projection.NormalizedProjection
org.apache.sis.referencing.operation.projection.AzimuthalEquidistant
org.apache.sis.referencing.operation.projection.ModifiedAzimuthalEquidistant
All Implemented Interfaces:
Serializable, Parameterized, LenientComparable, org.opengis.referencing.operation.MathTransform, org.opengis.referencing.operation.MathTransform2D
public class ModifiedAzimuthalEquidistant extends AzimuthalEquidistant
Modified Azimuthal Equidistant projection (EPSG:9832). This is an approximation of the oblique form of the Azimuthal Equidistant projection. For distances under 800 kilometres this modification introduces no significant error.

Limitation

This class does not support derivative (Jacobian matrix) yet. See SIS-237 on issues tracker.
Since:
1.1
Version:
1.1
See Also:

  • Field Details

    • serialVersionUID

      private static final long serialVersionUID
      For compatibility with different versions during deserialization.
      See Also:

    • ℯ2_ν0_sinφ0

      private final double ℯ2_ν0_sinφ0
      A term involving radius of curvature ν₀, the latitude of origin φ₀ and the eccentricity. The semi-major axis length a is omitted since it is handled outside this class.

    • G

      private final double G
      The ℯ⋅sin(φ₀)/√(1 − ℯ²) term, used in direct projection.

    • Hp

      private final double Hp
      The ℯ⋅cos(φ₀)/√(1 − ℯ²) term. This is the H term in EPSG guidance notes but without the cos(α) term (omitted because α depends on the point to project).

      Note that during reverse projection, EPSG guidance notes has a A as: −ℯ²⋅cos²φ₀/(1 − ℯ²)⋅cos²α. We opportunistically use Hp² for that purpose.

    • Bp

      private final double Bp
      The 3⋅ℯ²⋅sin(φ₀)⋅cos(φ₀)/(1 − ℯ²) term. This is the B term in EPSG guidance notes for reverse projection but without the terms that depend on coordinates of transformed point.

  • Constructor Details

    • ModifiedAzimuthalEquidistant

      public ModifiedAzimuthalEquidistant(org.opengis.referencing.operation.OperationMethod method, Parameters parameters)
      Creates a Modified Azimuthal Equidistant projection from the given parameters. The method argument can be the description of one of the following:
      • "Modified Azimuthal Equidistant".
      Parameters:
      method - description of the projection parameters.
      parameters - the parameter values of the projection to create.

    • ModifiedAzimuthalEquidistant

      @Workaround(library="JDK", version="1.8") private ModifiedAzimuthalEquidistant(Initializer initializer)
      Work around for RFE #4093999 in Sun's bug database ("Relax constraint on placement of this()/super() call in constructors").

  • Method Details

    • initializer

      @Workaround(library="JDK", version="1.8") private static Initializer initializer(org.opengis.referencing.operation.OperationMethod method, Parameters parameters)
      Work around for RFE #4093999 in Sun's bug database ("Relax constraint on placement of this()/super() call in constructors").

    • createMapProjection

      public org.opengis.referencing.operation.MathTransform createMapProjection(org.opengis.referencing.operation.MathTransformFactory factory) throws org.opengis.util.FactoryException
      Returns the sequence of normalization → this → denormalization 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 latter case, this transform may 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:
      org.opengis.util.FactoryException - if an error occurred while creating a transform.
      See Also:

    • transform

      public org.opengis.referencing.operation.Matrix transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, boolean derivate) throws ProjectionException
      Projects the specified (λ,φ) coordinates (units in radians) and stores the (x,y) result in dstPts. The results must be multiplied by the denormalization matrix before to get linear distances.
      Overrides:
      transform in class AzimuthalEquidistant
      Parameters:
      srcPts - source point coordinates, as (longitude, latitude) in radians.
      srcOff - the offset of the single coordinate tuple to be converted in the source array.
      dstPts - the array into which the converted coordinates is returned (may be the same than srcPts).
      dstOff - the offset of the location of the converted coordinates 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 coordinates cannot 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).
      Overrides:
      inverseTransform in class AzimuthalEquidistant
      Parameters:
      srcPts - the array containing the source point coordinates, 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 coordinates is returned (may be the same than srcPts).
      dstOff - the offset of the location of the converted point that is stored in the destination array.
      Throws:
      ProjectionException - if the point cannot be converted.