Class Mercator

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

    public class Mercator
    extends NormalizedProjection
    Mercator Cylindrical projection (EPSG codes 9804, 9805, 1026, 1024, 1044, 9841). See the Mercator projection on MathWorld for an overview.
    The parallels and the meridians are straight lines and cross at right angles; this projection thus produces rectangular charts. The scale is true along the equator (by default) or along two parallels equidistant of the equator (if a scale factor other than 1 is used).

    This projection is used to represent areas close to the equator. It is also often used for maritime navigation because all the straight lines on the chart are loxodrome lines, i.e. a ship following this line would keep a constant azimuth on its compass.

    This implementation handles both the 1 and 2 standard parallel cases. For Mercator (variant A) (EPSG code 9804), the line of contact is the equator. For Mercator (variant B) (EPSG code 9805) lines of contact are symmetrical about the equator.

    Behavior at poles
    The projection of 90°N gives positive infinity. The projection of 90°S gives negative infinity. Projection of a latitude outside the [-90 … 90]° range produces NaN.
    See Also:
    Transverse­Mercator, Oblique­Mercator, Serialized Form

    Defined in the sis-referencing module

    • Constructor Detail

      • Mercator

        public Mercator​(OperationMethod method,
                        Parameters parameters)
        Creates a Mercator projection from the given parameters. The method argument can be the description of one of the following:
        • "Mercator (variant A)", also known as "Mercator (1SP)".
        • "Mercator (variant B)", also known as "Mercator (2SP)".
        • "Mercator (variant C)".
        • "Mercator (Spherical)".
        • "Popular Visualisation Pseudo Mercator".
        • "Miller Cylindrical".
        method - description of the projection parameters.
        parameters - the parameter values of the projection to create.
    • Method Detail

      • transform

        public void transform​(double[] srcPts,
                              int srcOff,
                              double[] dstPts,
                              int dstOff,
                              int numPts)
                       throws TransformException
        Converts a list of coordinate points. This method performs the same calculation than above transform(double[], int, double[], int, boolean) method, but is overridden for efficiency.
        Specified by:
        transform in interface Math­Transform
        transform in class Abstract­Math­Transform
        src­Pts - the array containing the source point coordinates.
        src­Off - the offset to the first point to be transformed in the source array.
        dst­Pts - the array into which the transformed point coordinates are returned. May be the same than src­Pts.
        dst­Off - the offset to the location of the first transformed point that is stored in the destination array.
        num­Pts - the number of point objects to be transformed.
        Transform­Exception - if a point can not be converted.
      • 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
        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.
        Projection­Exception - if the point can not be converted.