fr.cnes.sirius.patrius.projections

Class ProjectionEllipsoidUtils

java.lang.Object

fr.cnes.sirius.patrius.projections.ProjectionEllipsoidUtils

public final class ProjectionEllipsoidUtils
extends Object

This class provides utility methods needed for projections.

Since:

4.3

Version:

$Id$

Author:

Thomas Galpin

See Also:

EllipsoidBodyShape

Concurrency :

not thread-safe

Field Summary

Fields

Modifier and Type	Field and Description
static double	GEODETIC_PRECISION Local precision for geodetic problem computation (in meters).

Method Summary

Modifier and Type	Method and Description
static double	computeBearing(GeodeticPoint gv1, GeodeticPoint gv2, EllipsoidBodyShape shape) Compute the bearing (azimuth) between two geodetic Points.
static GeodeticPoint	computeCenterPointAlongLoxodrome(GeodeticPoint p1, GeodeticPoint p2, EllipsoidBodyShape body) Compute center point between two points along a loxodrome.
static double	computeInverseMeridionalDistance(double distance, EllipsoidBodyShape shape) Compute the geodetic latitude, from a distance from the equator.
static double	computeInverseRectifyingLatitude(double rectifyingLat, EllipsoidBodyShape shape) compute geodetic latitude at a given rectifying latitude. rectifying latitude -> giving sphere that has correct distances along the meridians
static double	computeLoxodromicDistance(GeodeticPoint p1, GeodeticPoint p2, EllipsoidBodyShape shape) Loxodromic distance between P1 and P2.This is the distance of constant bearing (or along a line in Mercator).
static double	computeMercatorLatitude(double geodeticLat, EllipsoidBodyShape shape) Compute crescent latitude (Le) at a given geodetic latitude. also called Mercator latitude.
static double	computeMeridionalDistance(double geodeticLat, EllipsoidBodyShape shape) Compute the distance from a given geodetic latitude to the equator, along a meridian.
static double	computeOrthodromicDistance(double lat1, double lon1, double lat2, double lon2, EllipsoidBodyShape shape) Compute the orthodromic distance.
static double	computeOrthodromicDistance(GeodeticPoint p1, GeodeticPoint p2, EllipsoidBodyShape shape) Compute the orthodromic distance between two points.
static GeodeticPoint	computePointAlongLoxodrome(GeodeticPoint p1, double distance, double azimuth, EllipsoidBodyShape shape) Compute the point coordinates from an origin point, an azimuth and a distance along the rhumb line (Loxodrome).
static GeodeticPoint	computePointAlongOrthodrome(GeodeticPoint p1, double distance, double azimuthDirection, EllipsoidBodyShape shape) Compute a geodetic point along orthodrome, from a point p1, at a distance d, in a direction defined from an azimuth.
static double	computeRadiusEastWest(double geodeticLat, EllipsoidBodyShape shape) Compute radius of curvature section East/West (also called M or Re).
static double	computeSphericalAzimuth(GeodeticPoint p1, GeodeticPoint p2) Compute the spherical azimuth (clock wise) between two points.
static List<GeodeticPoint>	discretizeGreatCircle(GeodeticPoint from, GeodeticPoint to, double maxLength, EllipsoidBodyShape shape) Discretize a great circle into N segments, between two points.
static List<GeodeticPoint>	discretizeRhumbLine(GeodeticPoint from, GeodeticPoint to, double maxLength, EllipsoidBodyShape shape) Discretize a rhumb line into N segments, between two points.
static double	getEccentricity(EllipsoidBodyShape shape) Get the eccentricity.
static double[]	getSeries(EllipsoidBodyShape shape) Getter for series.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

GEODETIC_PRECISION

public static final double GEODETIC_PRECISION

Local precision for geodetic problem computation (in meters).

See Also:

Constant Field Values

Method Detail

computeBearing

public static final double computeBearing(GeodeticPoint gv1,
                                          GeodeticPoint gv2,
                                          EllipsoidBodyShape shape)
                                   throws PatriusException

Compute the bearing (azimuth) between two geodetic Points.

Parameters:

gv1 - geodetic point 1

gv2 - geodetic point 2

shape - Body shape.

Returns:

the azimuth angle as a double. Convention used : azimuth is angle from the north direction to the current direction in CLOCKWISE sense.

Throws:

PatriusException - if points are too close from each other

computeSphericalAzimuth

public static double computeSphericalAzimuth(GeodeticPoint p1,
                                             GeodeticPoint p2)

Compute the spherical azimuth (clock wise) between two points.

Parameters:

p1 - first point

p2 - second point

Returns:

the spherical azimuth (clock wise)

computeMercatorLatitude

public static double computeMercatorLatitude(double geodeticLat,
                                             EllipsoidBodyShape shape)

Compute crescent latitude (Le) at a given geodetic latitude. also called Mercator latitude. See following link for demonstration of formula :

Parameters:

geodeticLat - geodetic latitude

shape - Body shape.

Returns:

crescent latitude (Le) also called Mercator latitude

See Also:

http://cartes-martinique.pagesperso-orange.fr/LatitudesCroissantes.htm

computeRadiusEastWest

public static double computeRadiusEastWest(double geodeticLat,
                                           EllipsoidBodyShape shape)

Compute radius of curvature section East/West (also called M or Re). Distance to the Intersection of normal to ellipsoid at the given latitude with pole axis.

Parameters:

geodeticLat - geodetic latitude must between : - PI/2 and PI/2

shape - Body shape.

Returns:

radius of curvatureEast/West (also called M or Re)

computeLoxodromicDistance

public static double computeLoxodromicDistance(GeodeticPoint p1,
                                               GeodeticPoint p2,
                                               EllipsoidBodyShape shape)
                                        throws PatriusException

Loxodromic distance between P1 and P2.This is the distance of constant bearing (or along a line in Mercator). This method comes from libSpace.

Parameters:

p1 - Point 1

p2 - Point 2

shape - Body shape.

Returns:

distance in meters along loxodromic

Throws:

PatriusException - if latitude of one point is not between -/+ 89.999 deg

computeMeridionalDistance

public static final double computeMeridionalDistance(double geodeticLat,
                                                     EllipsoidBodyShape shape)

Compute the distance from a given geodetic latitude to the equator, along a meridian.

Parameters:

geodeticLat - geodetic latitude must between : - PI/2 and PI/2

shape - Body shape.

Returns:

meridionalDistance (in meters)

computeInverseMeridionalDistance

public static final double computeInverseMeridionalDistance(double distance,
                                                            EllipsoidBodyShape shape)

Compute the geodetic latitude, from a distance from the equator.

Parameters:

distance - distance from the equator

shape - Body shape.

Returns:

geodetic latitude

computePointAlongLoxodrome

public static final GeodeticPoint computePointAlongLoxodrome(GeodeticPoint p1,
                                                             double distance,
                                                             double azimuth,
                                                             EllipsoidBodyShape shape)
                                                      throws PatriusException

Compute the point coordinates from an origin point, an azimuth and a distance along the rhumb line (Loxodrome). The computation is done on the geoid associated to the geodetic point. The method is issue from Snyder, Map Projection, A working manuel, p46/47. The method comes from libSpace The precision is

• 4 cm for 1000 km
• 4 mm for 100 km
• <1 mm for 1 km

but is slower than the simplified method (about 20%)

Parameters:

p1 - initial point

distance - distance along the rhumb line

azimuth - Convention used : azimuth is angle from the north direction to the current direction in CLOCKWISE sense.

shape - Body shape.

Returns:

the resulting geodetic point

Throws:

PatriusException - if computed latitudes are out of range

See Also:

https://pubs.er.usgs.gov/publication/pp1395

computeInverseRectifyingLatitude

public static double computeInverseRectifyingLatitude(double rectifyingLat,
                                                      EllipsoidBodyShape shape)

compute geodetic latitude at a given rectifying latitude. rectifying latitude -> giving sphere that has correct distances along the meridians

Parameters:

rectifyingLat - rectifying latitude

shape - Body shape.

Returns:

geodetic latitude (rad)

computeOrthodromicDistance

public static final double computeOrthodromicDistance(GeodeticPoint p1,
                                                      GeodeticPoint p2,
                                                      EllipsoidBodyShape shape)

Compute the orthodromic distance between two points. This code is issue from Vincenty's works. If points are equal it returns 0, else it calls the the Vincenty method, with more elementary parameters.

Parameters:

p1 - first point

p2 - second point

shape - Body shape.

Returns:

orthodromic distance on ellipsoid.

See Also:

http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf

computeOrthodromicDistance

public static final double computeOrthodromicDistance(double lat1,
                                                      double lon1,
                                                      double lat2,
                                                      double lon2,
                                                      EllipsoidBodyShape shape)

Compute the orthodromic distance. This code is issue from Vincenty's works.

Parameters:

lat1 - latitude point 1.

lon1 - longitude point 1.

lat2 - latitude point 2.

lon2 - longitude point 2.

shape - Body shape.

Returns:

Orthodromic distance on ellipsoid.

See Also:

http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf

computePointAlongOrthodrome

public static final GeodeticPoint computePointAlongOrthodrome(GeodeticPoint p1,
                                                              double distance,
                                                              double azimuthDirection,
                                                              EllipsoidBodyShape shape)

Compute a geodetic point along orthodrome, from a point p1, at a distance d, in a direction defined from an azimuth. This is the direct geodetic problem. This code is issue from Vincenty's works.

Parameters:

p1 - Origin point.

distance - Distance to compute resulting point.

azimuthDirection - azimuth direction, convention used : azimuth is angle from the north direction to the current direction in CLOCKWISE sense.

shape - Body shape.

Returns:

the geodetic point

See Also:

http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf

discretizeRhumbLine

public static final List<GeodeticPoint> discretizeRhumbLine(GeodeticPoint from,
                                                            GeodeticPoint to,
                                                            double maxLength,
                                                            EllipsoidBodyShape shape)
                                                     throws PatriusException

Discretize a rhumb line into N segments, between two points. The result returned contains the first and the last point.

Parameters:

from - first geodetic point

to - ending geodetic point

maxLength - This distance is used when a discretization occurs : i.e : when the line property is not coherent with the projection ( EnumLineProperty). This parameter represent a distance expressed in meters. This will be the maximal distance between two points of the projected polygon. If you set the parameter to a value <=0 no discretization will be done.

shape - Body shape.

Returns:

a list of geodetic points

Throws:

PatriusException - if points are too close from each other

discretizeGreatCircle

public static final List<GeodeticPoint> discretizeGreatCircle(GeodeticPoint from,
                                                              GeodeticPoint to,
                                                              double maxLength,
                                                              EllipsoidBodyShape shape)

Discretize a great circle into N segments, between two points. The result returned contains the first and the last point.

Parameters:

from - first geodetic point

to - ending geodetic point

maxLength - This distance is used when a discretization occurs : i.e : when the line property is not coherent with the projection ( EnumLineProperty). This parameter represent a distance expressed in meters. This will be the maximal distance between two points of the projected polygon. If you set the parameter to a value <=0, no discretization will be done.

shape - Body shape.

Returns:

a list of geodetic points

getEccentricity

public static double getEccentricity(EllipsoidBodyShape shape)

Get the eccentricity.

Parameters:

shape - Body shape.

Returns:

the eccentricity

getSeries

public static double[] getSeries(EllipsoidBodyShape shape)

Getter for series.

Parameters:

shape - Body shape.

Returns:

the series

computeCenterPointAlongLoxodrome

public static GeodeticPoint computeCenterPointAlongLoxodrome(GeodeticPoint p1,
                                                             GeodeticPoint p2,
                                                             EllipsoidBodyShape body)
                                                      throws PatriusException

Compute center point between two points along a loxodrome.

Parameters:

p1 - first point

p2 - second point

body - Earth body

Returns:

center point between two points along a loxodrome (warning: altitude is set to 0)

Throws:

PatriusException - thrown if computation failed