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:
  • Constructor Details

    • 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 Details

    • getEN

      protected static ENPair getEN(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 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
    • defaultEllipsoid

      public Ellipsoid defaultEllipsoid()
      Define the default Ellipsoid for this coordinate system
      Specified by:
      defaultEllipsoid in class CoordinateSystem
      Returns:
      default Ellipsoid
    • 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)