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	ELLIPSOID_PRECISION Local precision for ellipsoid problem computation (in meters).

Method Summary

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

Methods inherited from class java.lang.Object

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

Field Detail

ELLIPSOID_PRECISION

public static final double ELLIPSOID_PRECISION

Local precision for ellipsoid problem computation (in meters).

See Also:

Constant Field Values

Method Detail

computeBearing

public static final double computeBearing(EllipsoidPoint p1,
                                          EllipsoidPoint p2)
                                   throws PatriusException

Compute the bearing (azimuth) between two points.

Parameters:

p1 - first point

p2 - second point

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 aren't associated to the same body shape
if the body shape isn't a OneAxisEllipsoid
if points are too close from each other

computeSphericalAzimuth

public static double computeSphericalAzimuth(EllipsoidPoint p1,
                                             EllipsoidPoint p2)
                                      throws PatriusException

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

Parameters:

p1 - first point

p2 - second point

Returns:

the spherical azimuth (clock wise)

Throws:

PatriusException - if points aren't associated to the same body shape

computeMercatorLatitude

public static double computeMercatorLatitude(double ellipsoidLat,
                                             OneAxisEllipsoid shape)

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

Parameters:

ellipsoidLat - Ellipsoid 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 ellipsoidLat,
                                           OneAxisEllipsoid 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:

ellipsoidLat - Ellipsoid 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(EllipsoidPoint p1,
                                               EllipsoidPoint p2)
                                        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

Returns:

distance in meters along loxodromic

Throws:

PatriusException - if points aren't associated to the same body shape
if the body shape isn't a OneAxisEllipsoid
if latitude of one point is not between -/+ 89.999 deg

computeMeridionalDistance

public static final double computeMeridionalDistance(double ellipsoidLat,
                                                     OneAxisEllipsoid shape)

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

Parameters:

ellipsoidLat - Ellipsoid latitude must between : - PI/2 and PI/2

shape - Body shape

Returns:

meridionalDistance (in meters)

computeInverseMeridionalDistance

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

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

Parameters:

distance - Distance from the equator

shape - Body shape

Returns:

ellipsoid latitude

computePointAlongLoxodrome

public static final EllipsoidPoint computePointAlongLoxodrome(EllipsoidPoint p1,
                                                              double distance,
                                                              double azimuth)
                                                       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 ellipsoid 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

Returns:

the resulting point

Throws:

PatriusException - if the body shape isn't a OneAxisEllipsoid
if computed latitudes are out of range

See Also:

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

computeInverseRectifyingLatitude

public static double computeInverseRectifyingLatitude(double rectifyingLat,
                                                      OneAxisEllipsoid shape)

compute ellipsoid 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:

ellipsoid latitude (rad)

computeOrthodromicDistance

public static final double computeOrthodromicDistance(EllipsoidPoint p1,
                                                      EllipsoidPoint p2)
                                               throws PatriusException

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

Returns:

orthodromic distance on ellipsoid.

Throws:

PatriusException - if points aren't associated to the same body shape if the body shape isn't a OneAxisEllipsoid

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,
                                                      OneAxisEllipsoid 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:

the orthodromic distance on ellipsoid

See Also:

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

computePointAlongOrthodrome

public static final EllipsoidPoint computePointAlongOrthodrome(EllipsoidPoint p1,
                                                               double distance,
                                                               double azimuthDirection)
                                                        throws PatriusException

Compute a point along orthodrome, from a point p1, at a distance d, in a direction defined from an azimuth. This is the direct ellipsoid 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

Returns:

the point

Throws:

PatriusException - if the body shape isn't a OneAxisEllipsoid

See Also:

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

discretizeRhumbLine

public static final List<EllipsoidPoint> discretizeRhumbLine(EllipsoidPoint from,
                                                             EllipsoidPoint to,
                                                             double maxLength)
                                                      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 point

to - Ending 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.

Returns:

a list of points

Throws:

PatriusException - if points aren't associated to the same body shape
if points are too close from each other

discretizeGreatCircle

public static final List<EllipsoidPoint> discretizeGreatCircle(EllipsoidPoint from,
                                                               EllipsoidPoint to,
                                                               double maxLength)
                                                        throws PatriusException

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

Parameters:

from - First point

to - Ending 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.

Returns:

a list of points

Throws:

PatriusException - if points aren't associated to the same body shape

getEccentricity

public static double getEccentricity(OneAxisEllipsoid shape)

Getter for the eccentricity.

Parameters:

shape - Body shape

Returns:

the eccentricity

getSeries

public static double[] getSeries(OneAxisEllipsoid shape)

Getter for the series.

Parameters:

shape - Body shape

Returns:

the series

computeCenterPointAlongLoxodrome

public static EllipsoidPoint computeCenterPointAlongLoxodrome(EllipsoidPoint p1,
                                                              EllipsoidPoint p2)
                                                       throws PatriusException

Compute center point between two points along a loxodrome.

Parameters:

p1 - First point

p2 - Second point

Returns:

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

Throws:

PatriusException - if computation failed