TLcdGnomonic (LuciadLightspeed API documentation)

java.lang.Object
- com.luciad.projection.ALcdProjection
- - com.luciad.projection.ALcdAzimuthal
  - - com.luciad.projection.TLcdGnomonic

All Implemented Interfaces:

ILcdAzimuthal, ILcdProjection, ILcdPropertyChangeSource, Serializable, Cloneable
```
public class TLcdGnomonic
extends ALcdAzimuthal
```
Gnomonic projection.

Introduction

This projection is an azimuthal and perspective projection from the center of the globe onto a plane tangent to the surface in a point.

Properties
- All meridians and the equator are straight lines. In fact all great circles are shown as straight lines.
- The shortest route between any two points on the surface of a sphere corresponds to the shortest route on the map. This stems from the fact that the shortest route between any two points on a sphere lies on a great circle. Therefore it is projected as a straight line. This seems to be the only useful feature of this projection.
- Directions from the center of the projection are true.
- The projection is neither conformal nor equal-area.
- Less than a hemisphere can be shown on the map.
Example

Sample code
```
 ILcdProjection projection =
     new TLcdGnomonic(20.0, -50.0);
 
```
Implementation aspects

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

Limitations

In practice only the spherical form is used. So, only the spherical form is implemented.
See Also:

Serialized Form

Field Summary
- Fields inherited from class com.luciad.projection.ALcdProjection
  fPropertyChangeDispatcher
- Fields inherited from interface com.luciad.projection.ILcdProjection
  EPSILON

Constructor Summary

Constructors
Constructor and Description
`TLcdGnomonic()` Constructs a gnomonic projection for the sphere with the origin at a point `(0.0, 0.0)`.
`TLcdGnomonic(double aLongitude, double aLatitude)` Constructs a gnomonic projection for the sphere with the origin at a point `(aLatitude, aLongitude)`.
`TLcdGnomonic(ILcdPoint aOrigin)` Constructs a gnomonic projection for a sphere with the origin at an `ILcdPoint` `aOrigin`.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`double[][]`	`boundaryLats(double aLon)` Default implementation.
`double[][]`	`boundaryLons(double aLat)` Default implementation.
`protected void`	`calculateCachedValues()` Constants based on the point of origin of the projection don't have to be recalculated every time a method is called.
`boolean`	`inLonLatBounds(ILcdPoint aLLP)` Checks if an `ILcdPoint` is inside the valid area of geodetic coordinates of the projection.
`boolean`	`inWorldBoundsOnSphere(ILcdPoint aXYPoint, double aRadius)` Checks if a `ILcdPoint` is inside the valid cartesian area of the projection.
`boolean`	`isAllInBounds()` If all geodetic coordinates (l ,j ) are projected (visible) by an `ILcdProjection` and all (x,y ) coordinates are bounded this is `true`.
`void`	`lonlatheight2worldOnSphereSFCT(ILcdPoint aLLHP, double aRadius, ILcd2DEditablePoint aXYPointSFCT)` Transforms an `ILcd2DEditablePoint` on a sphere into the cartesian coordinate system of the projection.
`String`	`toString()` Returns the `String` representation of the gnomonic projection.
`void`	`world2DEditableBoundsOnSphereSFCT(double aRadius, ILcd2DEditableBounds aWorldBound)` Less than one hemisphere is shown around the center of the projection.
`void`	`world2lonlatOnSphereSFCT(ILcdPoint aXYPoint, double aRadius, ILcd2DEditablePoint aLLPSFCT)` Transforms an `ILcdPoint` from the cartesian coordinate system of the projection into an `ILcd2DEditablePoint` onto a sphere.

Methods inherited from class com.luciad.projection.ALcdAzimuthal
clone, equals, getOrigin, getOriginLat, getOriginLon, hashCode, isContinuous, loadProperties, setOriginLat, setOriginLon, writePropertiesSFCT

Methods inherited from class com.luciad.projection.ALcdProjection
addPropertyChangeListener, firePropertyChangeEvent, inWorldBoundsOnEllipsoid, lonlatheight2worldOnEllipsoidSFCT, removePropertyChangeListener, world2DEditableBoundsOnEllipsoidSFCT, world2lonlatOnEllipsoidSFCT

Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.luciad.projection.ILcdProjection
inWorldBoundsOnEllipsoid, lonlatheight2worldOnEllipsoidSFCT, world2DEditableBoundsOnEllipsoidSFCT, world2lonlatOnEllipsoidSFCT

Methods inherited from interface com.luciad.util.ILcdPropertyChangeSource
addPropertyChangeListener, removePropertyChangeListener

- Constructor Detail
  - TLcdGnomonic
```
public TLcdGnomonic()
```
    Constructs a gnomonic projection for the sphere with the origin at a point (0.0, 0.0).
  - TLcdGnomonic
```
public TLcdGnomonic(double aLongitude,
                    double aLatitude)
```
    Constructs a gnomonic projection for the sphere with the origin at a point (aLatitude, aLongitude). The central meridian is at aLongitude.
    
    Parameters:
    
    aLongitude - longitude of the origin of the projection, in decimal degrees.
    
    aLatitude - latitude of the origin of the projection, in decimal degrees.
  - TLcdGnomonic
```
public TLcdGnomonic(ILcdPoint aOrigin)
```
    Constructs a gnomonic projection for a sphere with the origin at an ILcdPoint aOrigin. The central meridian is at aOrigin.getX().
    
    Parameters:
    
    aOrigin - ILcdPoint of the origin of the projection. No side effects will happen to the projection as a result from external changes to aOrigin.
- Method Detail
  - 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 aXYPointSFCT)
                                    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).
    
    aXYPointSFCT - 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.
  - 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 .
  - 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.
  - world2DEditableBoundsOnSphereSFCT
```
public void world2DEditableBoundsOnSphereSFCT(double aRadius,
                                              ILcd2DEditableBounds aWorldBound)
```
    Less than one hemisphere is shown around the center of the projection.
    
    Parameters:
    
    aRadius - radius of the sphere.
    
    aWorldBound - the bounds of the projection in world coordinates as side effect.
  - toString
```
public String toString()
```
    Returns the String representation of the gnomonic projection.
    
    Specified by:
    
    toString in interface ILcdProjection
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    the String representation of the gnomonic projection.

LuciadLightspeedClass TLcdGnomonic

Introduction

Properties

Example

Sample code

Implementation aspects

Limitations

Field Summary

Fields inherited from class com.luciad.projection.ALcdProjection

Fields inherited from interface com.luciad.projection.ILcdProjection

Constructor Summary

Method Summary

Methods inherited from class com.luciad.projection.ALcdAzimuthal

Methods inherited from class com.luciad.projection.ALcdProjection

Methods inherited from class java.lang.Object

Methods inherited from interface com.luciad.projection.ILcdProjection

Methods inherited from interface com.luciad.util.ILcdPropertyChangeSource

Constructor Detail

TLcdGnomonic

TLcdGnomonic

TLcdGnomonic

Method Detail

calculateCachedValues

isAllInBounds

lonlatheight2worldOnSphereSFCT

world2lonlatOnSphereSFCT

inLonLatBounds

boundaryLons

boundaryLats

inWorldBoundsOnSphere

world2DEditableBoundsOnSphereSFCT

toString