Package com.luciad.projection

Class TLcdAzimuthalEquidistant

java.lang.Object
com.luciad.projection.ALcdProjection
com.luciad.projection.ALcdAzimuthal
com.luciad.projection.TLcdAzimuthalEquidistant
All Implemented Interfaces:
ILcdAzimuthal, ILcdProjection, ILcdPropertyChangeSource, Serializable, Cloneable
public class TLcdAzimuthalEquidistant extends ALcdAzimuthal
Azimuthal Equidistant projection.

Introduction

Azimuthal equidistant projection with a point of origin for the projection. All distances and directions from the origin of projection on the map are shown correctly.

Properties

  • Distances measured from the origin are true.
  • Distances not measured along radii from the center are not true.
  • Only the projected point of origin has no distortion.
  • Directions from the center are true.
  • Neither equal-area nor conformal.
  • All great circles through the origin of projection are projected as straight lines.
  • Parallels on the polar projection are circles.
  • The outer meridian of a hemisphere on the equatorial aspect is a circle.
  • All other meridians and parallels are complex curves.
  • Not a perspective projection.
  • The point opposite the center is shown as a circle surrounding the map.

Example

Sample code


 ILcdProjection projection =
     new TLcdAzimuthalEquidistant(10.0, -30.0);

Implementation aspects

The equations of the azimuthal equidistant projection are taken from [Snyder1987].

See Also:

  • Constructor Details

    • TLcdAzimuthalEquidistant

      public TLcdAzimuthalEquidistant()
      Constructs an azimuthal equidistant projection with the origin at point (0.0, 0.0).

    • TLcdAzimuthalEquidistant

      public TLcdAzimuthalEquidistant(double aLongitude, double aLatitude)
      Constructs an azimuthal equidistant projection with the origin at a point (aLatitude, aLongitude). The central meridian is at the longitude aLongitude.
      Parameters:
      aLongitude - longitude of the origin of the projection, in decimal degrees.
      aLatitude - latitude of the origin of the projection, in decimal degrees.

    • TLcdAzimuthalEquidistant

      public TLcdAzimuthalEquidistant(ILcdPoint aOrigin)
      Constructs an azimuthal equidistant projection with the origin at an ILcdPoint aOrigin. The central meridian is at aOrigin.getX().
      Parameters:
      aOrigin - ILcdPoint of the origin of the projection. aOrigin is cloned within the constructor, so no side effects will happen to the projection as a result from changes to aOrigin.

  • Method Details

    • calculateCachedValues

      protected void calculateCachedValues()
      Description copied from class: ALcdAzimuthal
      Constants based on the point of origin of the projection don't have to be recalculated every time a method is called. They only have to be calculated when the projection properties change. Within the methods the pre-calculated values then can be used in order to gain efficiency.
      Overrides:
      calculateCachedValues in class ALcdAzimuthal

    • isAllInBounds

      public boolean isAllInBounds()
      Description copied from interface: ILcdProjection
      If all geodetic coordinates (l ,j ) are projected (visible) by an ILcdProjection and all (x,y ) coordinates are bounded this is true. All ILcdProjection objects have bounded (x,y ) coordinates because the projection is cut off if necessary.
      Returns:
      true if all LonLatPoints are within the bounds of the projection, false otherwise.

    • lonlatheight2worldOnSphereSFCT

      public void lonlatheight2worldOnSphereSFCT(ILcdPoint aLLHP, double aRadius, ILcd2DEditablePoint aWorldPoint) throws TLcdOutOfBoundsException
      Description copied from interface: ILcdProjection
      Transforms an ILcd2DEditablePoint on a sphere into the cartesian coordinate system of the projection.
      Parameters:
      aLLHP - point to be projected.
      aRadius - radius of the sphere (meters).
      aWorldPoint - projected point as side effect.
      Throws:
      TLcdOutOfBoundsException - If the ILcdPoint aLLHP is not within the valid area of the projection (visible area), then this exception is thrown.

    • lonlatheight2worldOnEllipsoidSFCT

      public void lonlatheight2worldOnEllipsoidSFCT(ILcdPoint aLLHP, ILcdEllipsoid aEllipsoid, ILcd2DEditablePoint aWorldPoint) throws TLcdOutOfBoundsException
      Description copied from class: ALcdProjection
      Default implementation calls lonlatheight2worldOnEllipsoidSFCT with aEllipsoid.getAuxRadius() as sphere radius.
      Specified by:
      lonlatheight2worldOnEllipsoidSFCT in interface ILcdProjection
      Overrides:
      lonlatheight2worldOnEllipsoidSFCT in class ALcdProjection
      Parameters:
      aLLHP - point to be projected.
      aEllipsoid - ellipsoid on which the point is defined.
      aWorldPoint - projected point as side effect.
      Throws:
      TLcdOutOfBoundsException - If the ILcdPoint aLLHP is not within the valid area of the projection (visible area), then this exception is thrown.

    • world2lonlatOnSphereSFCT

      public void world2lonlatOnSphereSFCT(ILcdPoint aXYPoint, double aRadius, ILcd2DEditablePoint aLLPSFCT) throws TLcdOutOfBoundsException
      Description copied from interface: ILcdProjection
      Transforms an ILcdPoint from the cartesian coordinate system of the projection into an ILcd2DEditablePoint onto a sphere.
      Parameters:
      aXYPoint - projected point for which the corresponding geodetic point is sought.
      aRadius - radius of the sphere (meters).
      aLLPSFCT - resulting geodetic coordinate as side effect.
      Throws:
      TLcdOutOfBoundsException - If the ILcdPoint aXYPoint is not within the valid area of the projection (visible area), then this exception is thrown.

    • world2lonlatOnEllipsoidSFCT

      public void world2lonlatOnEllipsoidSFCT(ILcdPoint aXYPoint, ILcdEllipsoid aEllipsoid, ILcd2DEditablePoint aLLPSFCT) throws TLcdOutOfBoundsException
      Description copied from class: ALcdProjection
      Default implementation calls world2lonlatOnSphereSFCT with aEllipsoid.getAuxRadius() as sphere radius.
      Specified by:
      world2lonlatOnEllipsoidSFCT in interface ILcdProjection
      Overrides:
      world2lonlatOnEllipsoidSFCT in class ALcdProjection
      Parameters:
      aXYPoint - projected point for which the corresponding geodetic point is sought.
      aEllipsoid - ellipsoid on which the geodetic coordinate is defined.
      aLLPSFCT - resulting geodetic coordinate as side effect.
      Throws:
      TLcdOutOfBoundsException - If the ILcdPoint aXYPoint is not within the valid area of the projection (visible area), then this exception is thrown.

    • inLonLatBounds

      public boolean inLonLatBounds(ILcdPoint aLLHP)
      Checks if an ILcd2DEditablePoint is inside the valid area of the transformation of the projection.
      Parameters:
      aLLHP - ILcd2DEditablePoint to be checked upon.
      Returns:
      true if valid, false if invalid.

    • boundaryLons

      public double[][] boundaryLons(double lat)
      Description copied from class: ALcdProjection
      Default implementation. To be redefined for specific projections.
      Specified by:
      boundaryLons in interface ILcdProjection
      Overrides:
      boundaryLons in class ALcdProjection
      Parameters:
      lat - latitude in decimal degrees and -90.0 <= aLat<= 90.0.
      Returns:
      the array of pairs of longitudes[0] and longitudes[1], where the closed interval longitudes[0] -> longitudes[1] is in visible area and -180.0 <= lon[i] <= 180.0.

    • boundaryLats

      public double[][] boundaryLats(double lon)
      Description copied from class: ALcdProjection
      Default implementation. To be redefined for specific projections.
      Specified by:
      boundaryLats in interface ILcdProjection
      Overrides:
      boundaryLats in class ALcdProjection
      Parameters:
      lon - longitude in decimal degrees -180.0 <= lon <= 180.0 .
      Returns:
      the array of pairs of latitudes lats[0] and lats[1], where the closed interval lats[0] -> lats[1] is in visible area and -90.0 <= lats[i] <= 90.0 .

    • world2DEditableBoundsOnSphereSFCT

      public void world2DEditableBoundsOnSphereSFCT(double aRadius, ILcd2DEditableBounds aWorldBound)
      The whole earth globe is projected except the point opposite the origin.
      Parameters:
      aRadius - radius of the sphere.
      aWorldBound - the bounds of the projection in world coordinates as side effect.

    • inWorldBoundsOnSphere

      public boolean inWorldBoundsOnSphere(ILcdPoint aXYPoint, double aRadius)
      Description copied from interface: ILcdProjection
      Checks if a ILcdPoint is inside the valid cartesian area of the projection. The valid cartesian area is determined naturally by the projection bounds or by an artificial introduced boundary limit because some cartesian points are at infinity. The shape of the valid cartesian area is in many cases rectangular or circular although it might be more complex.
      Parameters:
      aXYPoint - point to be checked upon.
      aRadius - radius of the sphere.
      Returns:
      true if valid, false if invalid.

    • toString

      public String toString()
      Returns the String representation of the azimuthal equidistant projection.
      Specified by:
      toString in interface ILcdProjection
      Overrides:
      toString in class Object
      Returns:
      String representation of this ILcdProjection.