Package com.luciad.projection

Class TLcdVerticalPerspective

java.lang.Object
com.luciad.projection.ALcdProjection
com.luciad.projection.ALcdPerspective
com.luciad.projection.TLcdVerticalPerspective
All Implemented Interfaces:
ILcdAzimuthal, ILcdPerspective, ILcdProjection, ILcdPropertyChangeSource, Serializable, Cloneable
public class TLcdVerticalPerspective extends ALcdPerspective
Vertical perspective projection.

Introduction

The vertical perspective projection is an azimuthal projection with characteristics the origin of the projection and the point of perspective. The origin height is taken into account.

Properties

  • The projection is an Azimuthal projection.
  • Orthographic, Stereographic and Gnomonic projections are special forms of the Vertical perspective.
  • The central meridian and a particular parallel (if shown) are shown as straight lines.
  • Other meridians and parallels are usually shown as arcs of circles or ellipses, but some may be shown as parabolas or hyperbolas.
  • The projection is neither conformal (unless Stereographic), nor equal-area.
  • If the point of perspective is above the center of the sphere or ellipsoid, les than one hemisphere may be shown (unless Orthographic).
  • If the point of perspective is below the center of the globe, more than one hemisphere may be shown (cfr. Stereographic).
  • Directions from the center are true.
  • There is considarable distortion near the projection limit.

Example

Sample code


 ILcdProjection projection =
     new TLcdVerticalPerspective(40.0, -100.0, 0.0, 2.0);

Implementation aspects

The equations of the vertical perspective projection are taken from [Snyder1987].

Notes

The point of perspective has to be outside the earth ellipsoid.
So, its value should be outside the closed interval [-1.0,1.0].

See Also:

  • Constructor Details

    • TLcdVerticalPerspective

      public TLcdVerticalPerspective()
      Constructs a vertical perspective projection with the origin at a point (0.0, 0.0, 0.0) and the perspective distance at 2.0.

    • TLcdVerticalPerspective

      public TLcdVerticalPerspective(double aLongitude, double aLatitude, double aHeight, double aPerspectiveDistance)
      Constructs a vertical perspective projection with the origin at a point (aLatitude, aLongitude, aHeight).
      Parameters:
      aLongitude - longitude of the origin of the projection, in decimal degrees.
      aLatitude - latitude of the origin of the projection, in decimal degrees.
      aHeight - height of the origin point above the ellipsoid.
      aPerspectiveDistance - distance of the point of perspective from the center of the earth globe divided by the semi-major axis.

    • TLcdVerticalPerspective

      public TLcdVerticalPerspective(ILcdPoint aOrigin, double aPerspectiveDistance)
      Constructs a vertical perspective projection with the origin at an ILcdPoint aOrigin and a point of perspective at a distance (divided by the semi-major axis) from the center of the earth.
      Parameters:
      aOrigin - the point of origin for the projection (lon,lat,height).
      aPerspectiveDistance - distance of the point of perspective from the center of the earth globe divided by the semi-major axis.

  • Method Details

    • calculateCachedValues

      protected void calculateCachedValues()
      Description copied from class: ALcdPerspective
      Constants based on the longitude, latitude, height of the point of origin of projection and the distance of the point of perspective 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 precalculated values then can be used in order to gain efficiency.
      Overrides:
      calculateCachedValues in class ALcdPerspective

    • 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
      Transforms a world point to a LonLatHeightPoint. The height, which is taken into account, is supposed to be available in the input/output parameter aLLPSFCT.
      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 aLLP)
      Description copied from interface: ILcdProjection
      Checks if an ILcdPoint is inside the valid area of geodetic coordinates of the projection. The valid area is determined by the LonLatPoints that are visible and for which the corresponding cartesian coordinate is within the boundaries.
      Parameters:
      aLLP - ILcdPoint to be checked upon.
      Returns:
      true if valid, false if invalid.

    • boundaryLons

      public double[][] boundaryLons(double aLat)
      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:
      aLat - 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 aLon)
      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:
      aLon - 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 projection is bounded when the perspective distance is outside the closed interval [-1,1]. Currently a perspective distance within this closed interval [-1,1] is not supported.
      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 vertical perspective projection.
      Specified by:
      toString in interface ILcdProjection
      Overrides:
      toString in class Object
      Returns:
      the String representation of the vertical perspective projection.

    • clone

      public Object clone()
      Description copied from interface: ILcdProjection
      Makes a deep clone of this ILcdProjection.
      Specified by:
      clone in interface ILcdProjection
      Overrides:
      clone in class ALcdPerspective
      Returns:
      deep clone of this ILcdProjection.