Class SatelliteTracking

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

public class SatelliteTracking extends NormalizedProjection
Satellite-Tracking projection. This projection has been developed in 1977 by Snyder and has no associated EPSG code. This projection is neither conformal or equal-area, but has the property that ground tracks for satellites orbiting the Earth with the same orbital parameters are shown as straight lines on the map. Other properties are (Snyder 1987):
  • All meridians are equally spaced straight lines. They are parallel on cylindrical form and converging to a common point on conical form.
  • All parallels are straight but unequally spaced. They are parallel on cylindrical form and are concentric circular arcs on conical form.
  • Conformality occurs along two chosen parallels. Scale is correct along one of these parameters on the conical form and along both on the cylindrical form.

Limitations

This map projection supports only circular orbits. The Earth is assumed spherical. Areas close to poles can not be mapped.

References

John P. Snyder., 1987. Map Projections - A Working Manual chapter 28: Satellite-tracking projections.
Since:
1.1
See Also:

Defined in the sis-referencing module

  • Constructor Details

    • SatelliteTracking

      public SatelliteTracking(OperationMethod method, Parameters parameters)
      Creates a Satellite Tracking projection from the given parameters.
      Parameters:
      method - description of the projection parameters.
      parameters - the parameter values of the projection to create.
      Throws:
      Invalid­Parameter­Value­Exception - if some parameters have incompatible values.
  • Method Details

    • 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. The results must be multiplied by the denormalization matrix before to get linear distances.

      The y axis lies along the central meridian λ₀, y increasing northerly, and x axis intersects perpendicularly at latitude of origin φ₀, x increasing easterly.

      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 coordinates can not be converted.
      See Also:
    • 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).
      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 coordinates can not be converted.