Package org.geotools.referencing
Class GeodeticCalculator
- Object
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- GeodeticCalculator
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public class GeodeticCalculator extends Object
Performs geodetic calculations on an ellipsoid. This class encapsulates a generic ellipsoid and calculates the following properties:- Distance and azimuth between two points.
- Point located at a given distance and azimuth from an other point.
The calculation uses the following information:
- The starting position, which is always considered valid. It is initially set at (0,0) and can only be changed to another legitimate value.
- Only one of the following:
- The destination position, or
- An azimuth and distance.
Note: This class is not thread-safe. If geodetic calculations are needed in a multi-threads environment, create one distinct instance of
GeodeticCalculator
for each thread.- Since:
- 2.1
- Author:
- Daniele Franzoni, Martin Desruisseaux
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Constructor Summary
Constructors Constructor Description GeodeticCalculator()
Constructs a new geodetic calculator associated with the WGS84 ellipsoid.GeodeticCalculator(CoordinateReferenceSystem crs)
Constructs a new geodetic calculator expecting coordinates in the supplied CRS.GeodeticCalculator(Ellipsoid ellipsoid)
Constructs a new geodetic calculator associated with the specified ellipsoid.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description double
getAzimuth()
Returns the azimuth.CoordinateReferenceSystem
getCoordinateReferenceSystem()
Returns the coordinate reference system for all methods working onPosition
objects.Point2D
getDestinationGeographicPoint()
Returns the destination point.Position
getDestinationPosition()
Returns the destination position in user coordinates, which doesn't need to be geographic.Ellipsoid
getEllipsoid()
Returns the referenced ellipsoid.Shape
getGeodeticCurve()
Calculates the geodetic curve between two points in the referenced ellipsoid.Shape
getGeodeticCurve(int numberOfPoints)
Calculates the geodetic curve between two points in the referenced ellipsoid.List<Point2D>
getGeodeticPath(int numPoints)
Calculates the geodetic curve between two points in the referenced ellipsoid.GeographicCRS
getGeographicCRS()
Returns the geographic coordinate reference system for all methods working onPoint2D
objects.double
getMeridianArcLength(double latitude1, double latitude2)
Calculates the meridian arc length between two points in the same meridian in the referenced ellipsoid.double
getOrthodromicDistance()
Returns the orthodromic distance (expressed in meters).Point2D
getStartingGeographicPoint()
Returns the starting point in geographic coordinates.Position
getStartingPosition()
Returns the starting position in user coordinates, which doesn't need to be geographic.void
setDestinationGeographicPoint(double longitude, double latitude)
Set the destination point in geographic coordinates.void
setDestinationGeographicPoint(Point2D point)
Set the destination point in geographic coordinates.void
setDestinationPosition(Position position)
Set the destination position in user coordinates, which doesn't need to be geographic.void
setDirection(double azimuth, double distance)
Set the azimuth and the distance from the starting point.void
setStartingGeographicPoint(double longitude, double latitude)
Set the starting point in geographic coordinates.void
setStartingGeographicPoint(Point2D point)
Set the starting point in geographic coordinates.void
setStartingPosition(Position position)
Set the starting position in user coordinates, which doesn't need to be geographic.String
toString()
Returns a string representation of the current state of this calculator.
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Constructor Detail
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GeodeticCalculator
public GeodeticCalculator()
Constructs a new geodetic calculator associated with the WGS84 ellipsoid.
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GeodeticCalculator
public GeodeticCalculator(Ellipsoid ellipsoid)
Constructs a new geodetic calculator associated with the specified ellipsoid. All calculations done by the new instance are referenced to this ellipsoid.- Parameters:
ellipsoid
- The ellipsoid onto which calculates distances and azimuths.
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GeodeticCalculator
public GeodeticCalculator(CoordinateReferenceSystem crs)
Constructs a new geodetic calculator expecting coordinates in the supplied CRS. The ellipsoid will be inferred from the CRS.- Parameters:
crs
- The reference system for thePosition
objects.- Since:
- 2.2
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Method Detail
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getCoordinateReferenceSystem
public CoordinateReferenceSystem getCoordinateReferenceSystem()
Returns the coordinate reference system for all methods working onPosition
objects. This is the CRS specified at construction time.- Returns:
- The CRS for all
Position
s. - Since:
- 2.2
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getGeographicCRS
public GeographicCRS getGeographicCRS()
Returns the geographic coordinate reference system for all methods working onPoint2D
objects. This is inferred from the CRS specified at construction time.- Returns:
- The CRS for
Point2D
s. - Since:
- 2.3
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getEllipsoid
public Ellipsoid getEllipsoid()
Returns the referenced ellipsoid.- Returns:
- The referenced ellipsoid.
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setStartingGeographicPoint
public void setStartingGeographicPoint(double longitude, double latitude) throws IllegalArgumentException
Set the starting point in geographic coordinates. The azimuth, the orthodromic distance and the destination point are discarted. They will need to be specified again.- Parameters:
longitude
- The longitude in decimal degrees between -180 and +180°latitude
- The latitude in decimal degrees between -90 and +90°- Throws:
IllegalArgumentException
- if the longitude or the latitude is out of bounds.- Since:
- 2.3
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setStartingGeographicPoint
public void setStartingGeographicPoint(Point2D point) throws IllegalArgumentException
Set the starting point in geographic coordinates. The x and y coordinates must be the longitude and latitude in decimal degrees, respectively.This is a convenience method for
setStartingGeographicPoint(x,y)
.- Parameters:
point
- The starting point.- Throws:
IllegalArgumentException
- if the longitude or the latitude is out of bounds.- Since:
- 2.3
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setStartingPosition
public void setStartingPosition(Position position) throws TransformException
Set the starting position in user coordinates, which doesn't need to be geographic. The coordinate reference system is the one specified to the constructor.- Parameters:
position
- The position in user coordinate reference system.- Throws:
TransformException
- if the position can't be transformed.- Since:
- 2.3
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getStartingGeographicPoint
public Point2D getStartingGeographicPoint()
Returns the starting point in geographic coordinates. The x and y coordinates are the longitude and latitude in decimal degrees, respectively. If the starting point has never been set, then the default value is (0,0).- Returns:
- The starting point in geographic coordinates.
- Since:
- 2.3
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getStartingPosition
public Position getStartingPosition() throws TransformException
Returns the starting position in user coordinates, which doesn't need to be geographic. The coordinate reference system is the one specified to the constructor.- Returns:
- The starting position in user CRS.
- Throws:
TransformException
- if the position can't be transformed to user coordinates.- Since:
- 2.3
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setDestinationGeographicPoint
public void setDestinationGeographicPoint(double longitude, double latitude) throws IllegalArgumentException
Set the destination point in geographic coordinates. The azimuth and distance values will be updated as a side effect of this call. They will be recomputed the next timegetAzimuth()
orgetOrthodromicDistance()
are invoked.- Parameters:
longitude
- The longitude in decimal degreeslatitude
- The latitude in decimal degrees between -90 and +90°- Throws:
IllegalArgumentException
- if the longitude or the latitude is out of bounds.- Since:
- 2.3
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setDestinationGeographicPoint
public void setDestinationGeographicPoint(Point2D point) throws IllegalArgumentException
Set the destination point in geographic coordinates. The x and y coordinates must be the longitude and latitude in decimal degrees, respectively.This is a convenience method for
setDestinationGeographicPoint(x,y)
.- Parameters:
point
- The destination point.- Throws:
IllegalArgumentException
- if the longitude or the latitude is out of bounds.- Since:
- 2.3
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setDestinationPosition
public void setDestinationPosition(Position position) throws TransformException
Set the destination position in user coordinates, which doesn't need to be geographic. The coordinate reference system is the one specified to the constructor.- Parameters:
position
- The position in user coordinate reference system.- Throws:
TransformException
- if the position can't be transformed.- Since:
- 2.2
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getDestinationGeographicPoint
public Point2D getDestinationGeographicPoint() throws IllegalStateException
Returns the destination point. This method returns the point set by the last call to asetDestinationGeographicPoint(...)
method, except ifsetDirection(...)
has been invoked after. In this later case, the destination point will be computed from the starting point to the azimuth and distance specified.- Returns:
- The destination point. The x and y coordinates are the longitude and latitude in decimal degrees, respectively.
- Throws:
IllegalStateException
- if the azimuth and the distance have not been set.- Since:
- 2.3
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getDestinationPosition
public Position getDestinationPosition() throws TransformException
Returns the destination position in user coordinates, which doesn't need to be geographic. The coordinate reference system is the one specified to the constructor.- Returns:
- The destination position in user CRS.
- Throws:
TransformException
- if the position can't be transformed to user coordinates.- Since:
- 2.2
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setDirection
public void setDirection(double azimuth, double distance) throws IllegalArgumentException
Set the azimuth and the distance from the starting point. The destination point will be updated as a side effect of this call. It will be recomputed the next timegetDestinationGeographicPoint()
is invoked.- Parameters:
azimuth
- The azimuth in decimal degreesdistance
- The orthodromic distance in the same units as the ellipsoid axis (meters by default)- Throws:
IllegalArgumentException
- if the azimuth or the distance is out of bounds.- See Also:
getAzimuth()
,getOrthodromicDistance()
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getAzimuth
public double getAzimuth() throws IllegalStateException
Returns the azimuth. This method returns the value set by the last call tosetDirection(azimuth,distance)
, except ifsetDestinationGeographicPoint(...)
has been invoked after. In this later case, the azimuth will be computed from the starting point to the destination point.- Returns:
- The azimuth, in decimal degrees from -180° to +180°.
- Throws:
IllegalStateException
- if the destination point has not been set.
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getOrthodromicDistance
public double getOrthodromicDistance() throws IllegalStateException
Returns the orthodromic distance (expressed in meters). This method returns the value set by the last call tosetDirection(azimuth,distance)
, except ifsetDestinationGeographicPoint(...)
has been invoked after. In this later case, the distance will be computed from the starting point to the destination point.- Returns:
- The orthodromic distance, in the same units as the ellipsoid axis.
- Throws:
IllegalStateException
- if the destination point has not been set.
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getMeridianArcLength
public double getMeridianArcLength(double latitude1, double latitude2)
Calculates the meridian arc length between two points in the same meridian in the referenced ellipsoid.- Parameters:
latitude1
- The latitude of the first point (in decimal degrees).latitude2
- The latitude of the second point (in decimal degrees).- Returns:
- Returned the meridian arc length between latitude1 and latitude2
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getGeodeticCurve
public Shape getGeodeticCurve(int numberOfPoints)
Calculates the geodetic curve between two points in the referenced ellipsoid. A curve in the ellipsoid is a path which points contain the longitude and latitude of the points in the geodetic curve. The geodetic curve is computed from the starting point to the destination point.- Parameters:
numberOfPoints
- The number of vertex in the geodetic curve. NOTE: This argument is only a hint and may be ignored in future version (if we compute a real curve rather than a list of line segments).- Returns:
- The path that represents the geodetic curve from the starting point to the destination point.
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getGeodeticCurve
public Shape getGeodeticCurve()
Calculates the geodetic curve between two points in the referenced ellipsoid. A curve in the ellipsoid is a path which points contain the longitude and latitude of the points in the geodetic curve. The geodetic curve is computed from the starting point to the destination point.- Returns:
- The path that represents the geodetic curve from the starting point to the destination point.
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getGeodeticPath
public List<Point2D> getGeodeticPath(int numPoints)
Calculates the geodetic curve between two points in the referenced ellipsoid. A curve in the ellipsoid is a path which points contain the longitude and latitude of the points in the geodetic curve. The geodetic curve is computed from the starting point to the destination point.- Parameters:
numPoints
- The number of vertices between the start and destination points- Returns:
- vertices approximating the curve
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