Class Lambert

  • Direct Known Subclasses:
    Lambert93, LambertI, LambertII, LambertIIExtended, LambertIII, LambertIV

    public abstract class Lambert
    extends Projection

    An abstract base class for implementations of the Lambert Conformal Conic Projection

    A Lambert projection maps points on the ellipsoid onto a cone which touches the ellipsoid at two parallels of latitude. For countries with a large east-west extent, it provides smaller variations in grid convergence than the more common TransverseMercator projection - but over a limited range of latitude. IGN, France's national mapping agency, adopted the Lambert Conformal Conic projection but had to divide mainland France into three zones of latitude, with a fourth zone for the island of Corsica. These are implemented in this package as subclasses of Lambert (see LambertI, LambertII, LambertIII, LambertIV). To overcome the obvious inconvenience of having the country divided into four distinct coordinate zones, a fifth set of Lambert Conformal Conical projection coefficients LambertIIExtended was produced to provide a nationwide coordinate system but with greater degrees of distortion. Ironically, the Lambert Conical projections have not been well-supported by handheld GPS equipment and many French maps (such as the 1:25000 Blue Series) are now over-printed with a UTM grid.

    In 1996, IGN introduced a new coordinate system known as Lambert 93

    See Also:
    ETRS89 Lambert Conformal Conic Coordinate Reference System , Systemes de Projection (in French)
    • Constructor Detail

      • Lambert

        public Lambert​(Position p,
                       Ellipsoid e,
                       Datum d)
        Creates a new instance of Lambert based on Position, Ellipsoid and Datum
        Parameters:
        p - Position of this point
        e - The Ellipsoid to use
        d - The Datum associated with this instance
      • Lambert

        public Lambert​(ENPair en,
                       Ellipsoid sphere,
                       Datum datum)
        Create a new Lambert object based on Easting and Northing distances
        Parameters:
        en - Easting and Northing values
        sphere - The Ellipsoid to use
        datum - the Datum to use
    • Method Detail

      • getEN

        protected static ENPair getEN​(java.lang.String gridref)
                               throws GridFormatException
        Parse Lambert coordinates into easting and northing distances
        Parameters:
        gridref - A pair of Lambert coordinates (e.g. "X=435.212 Y=217.306"), specified in km.
        Returns:
        Easting and Northing distances (m)
        Throws:
        GridFormatException - Invalid coordinate format results in a GridFormatException being thrown
      • toEN

        public ENPair toEN()
        Provide easting and northing distances
        Specified by:
        toEN in class Projection
        Returns:
        Easting and Northing distances (in metres)
      • toString

        public java.lang.String toString()
        Provide a String representation in Lambert coordinates. These are of the form "X=eeee.eee Y=nnnn.nnn" where eeee.eee and nnnn.nnn are the easting and northing distances in km.
        Specified by:
        toString in class CoordinateSystem
        Returns:
        The coordinate String
      • calcCoords

        protected void calcCoords()
        Initialise coordinates for this Position
      • gridConvergence

        public double gridConvergence()
        Calculate grid convergence
        Specified by:
        gridConvergence in class Projection
        Returns:
        Grid convergence (degrees)
      • defaultDatum

        public Datum defaultDatum()
        Define the default datum for this coordinate system
        Specified by:
        defaultDatum in class CoordinateSystem
        Returns:
        default datum
      • phiU

        protected abstract double phiU()
        Define Upper standard parallel for this conical projection
        Returns:
        Upper Standard Parallel (radians)
      • phiL

        protected abstract double phiL()
        Define lower standard parallel for this projection
        Returns:
        Lower Standard Parallel (radians)
      • phiB

        protected abstract double phiB()
        Define latitude of false origin
        Returns:
        Latitude of false origin (radians)
      • lamda0

        protected abstract double lamda0()
        Define longitude of grid origin
        Returns:
        Longitude of grid origin (radians)
      • e0

        protected abstract double e0()
        Define false easting value
        Returns:
        False easting (m)
      • n0

        protected abstract double n0()
        Define false northing
        Returns:
        False northing distance (m)