Package org.openstreetmap.josm.data.projection.proj

Class CassiniSoldner

  • All Implemented Interfaces:
    Proj
    public class CassiniSoldner
extends AbstractProj
    Cassini-Soldner Projection (EPSG code 9806). The Cassini-Soldner Projection is the ellipsoidal version of the Cassini projection for the sphere. It is not conformal but as it is relatively simple to construct it was extensively used in the last century and is still useful for mapping areas with limited longitudinal extent. It has now largely been replaced by the conformal Transverse Mercator which it resembles. Like this, it has a straight central meridian along which the scale is true, all other meridians and parallels are curved, and the scale distortion increases rapidly with increasing distance from the central meridian.

    This class has been derived from the implementation of the Geotools project; git 8cbf52d, org.geotools.referencing.operation.projection.CassiniSoldner at the time of migration.

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private static double C1
      Constants used for the forward and inverse transform for the elliptical case of the Cassini-Soldner.
      private static double C2  
      private static double C3  
      private static double C4  
      private static double C5  
      private double ml0
      Meridian distance at the latitudeOfOrigin.
      private double phi0
      Latitude of origin.

    • Constructor Summary

      Constructors 
      Constructor Description
      CassiniSoldner()  

    • Method Detail

      • getName

        public java.lang.String getName()
        Description copied from interface: Proj
        Replies a human readable name of this projection.
        Returns:
        The projection name. must not be null.

      • getProj4Id

        public java.lang.String getProj4Id()
        Description copied from interface: Proj
        Replies the Proj.4 identifier.
        Returns:
        The Proj.4 identifier (as reported by cs2cs -lp). If no id exists, return null.

      • project

        public double[] project​(double phi,
                        double lam)
        Description copied from interface: Proj
        Convert lat/lon to east/north.
        Parameters:
        phi - the latitude in radians
        lam - the longitude in radians
        Returns:
        array of length 2, containing east and north value in meters, divided by the semi major axis of the ellipsoid.

      • invproject

        public double[] invproject​(double x,
                           double y)
        Description copied from interface: Proj
        Convert east/north to lat/lon.
        Parameters:
        x - east value in meters, divided by the semi major axis of the ellipsoid
        y - north value in meters, divided by the semi major axis of the ellipsoid
        Returns:
        array of length 2, containing lat and lon in radians.

      • getAlgorithmBounds

        public Bounds getAlgorithmBounds()
        Description copied from interface: Proj
        Return the bounds where this projection is applicable. This is a fallback for when the projection bounds are not specified explicitly. In this area, the round trip lat/lon → east/north → lat/lon should return the starting value with small error. In addition, regions with extreme distortions should be excluded, if possible. It need not be the absolute maximum, but rather an area that is safe to display in JOSM and contain everything that one would expect to use.
        Returns:
        the bounds where this projection is applicable, null if unknown