ucar.unidata.geoloc.projection
Class Stereographic

java.lang.Object
  ucar.unidata.geoloc.ProjectionImpl
      ucar.unidata.geoloc.projection.Stereographic

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, Projection

public class Stereographic
extends ProjectionImpl

Stereographic projection, spherical earth. Projection plane is a plane tangent to the earth at latt, lont. see John Snyder, Map Projections used by the USGS, Bulletin 1532, 2nd edition (1983), p 153

Author:

John Caron

See Also:

Projection, ProjectionImpl, Serialized Form

Field Summary

Fields inherited from class ucar.unidata.geoloc.ProjectionImpl

ATTR_NAME, EARTH_RADIUS, INDEX_LAT, INDEX_LON, INDEX_X, INDEX_Y, PI, PI_OVER_2, PI_OVER_4

Constructor Summary

Stereographic()
Constructor with default parameters = North Polar

Stereographic(double latt, double lont, double scale)
Construct a Stereographic Projection.

Method Summary

java.lang.Object	clone() Clone this projection
ProjectionImpl	constructCopy() copy constructor - avoid clone !!
boolean	crossSeam(ProjectionPoint pt1, ProjectionPoint pt2) Does the line between these two points cross the projection "seam".
boolean	equals(java.lang.Object proj) Returns true if this represents the same Projection as proj.
static Stereographic	factory(double latt, double lont, double latTrue) Construct a Stereographic Projection using latitude of true scale and calculating scale factor.
double	getScale() Get the scale
double	getTangentLat() Get the tangent latitude
double	getTangentLon() Get the tangent longitude
double[][]	latLonToProj(double[][] from, double[][] to, int latIndex, int lonIndex) Convert lat/lon coordinates to projection coordinates.
float[][]	latLonToProj(float[][] from, float[][] to, int latIndex, int lonIndex) Convert lat/lon coordinates to projection coordinates.
ProjectionPoint	latLonToProj(LatLonPoint latLon, ProjectionPointImpl result) Convert a LatLonPoint to projection coordinates
java.lang.String	paramsToString() Get the parameters as a String
double[][]	projToLatLon(double[][] from, double[][] to) Convert projection coordinates to lat/lon coordinate.
float[][]	projToLatLon(float[][] from, float[][] to) Convert projection coordinates to lat/lon coordinate.
LatLonPoint	projToLatLon(ProjectionPoint world, LatLonPointImpl result) Convert projection coordinates to a LatLonPoint Note: a new object is not created on each call for the return value.
void	setScale(double scale) Set the scale
void	setTangentLat(double lat) Set the tangent latitude
void	setTangentLon(double lon) Set the tangent longitude

Methods inherited from class ucar.unidata.geoloc.ProjectionImpl

getClassName, getDefaultMapArea, getDefaultMapAreaLL, getHeader, getLatLonBoundingBox, getName, getProjectionParameters, getProjectionTypeLabel, isLatLon, latLonToProj, latLonToProj, latLonToProj, latLonToProj, latLonToProj, latLonToProj, latLonToProj, latLonToProj, latLonToProjBB, projToLatLon, projToLatLon, projToLatLon, projToLatLon, projToLatLonBB, setDefaultMapArea, setName, toString

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Stereographic

public Stereographic()

Constructor with default parameters = North Polar

Stereographic

public Stereographic(double latt,
                     double lont,
                     double scale)

Construct a Stereographic Projection.

Parameters:

latt - tangent point of projection, also origin of projecion coord system

lont - tangent point of projection, also origin of projecion coord system

scale - scale factor at tangent point, "normally 1.0 but may be reduced"

Method Detail

constructCopy

public ProjectionImpl constructCopy()

copy constructor - avoid clone !!

Specified by:

constructCopy in class ProjectionImpl

Returns:

a copy of this Projection

factory

public static Stereographic factory(double latt,
                                    double lont,
                                    double latTrue)

Construct a Stereographic Projection using latitude of true scale and calculating scale factor.

Since the scale factor at lat = k = 2*k0/(1+sin(lat)) [Snyder,Working Manual p157] then to make scale = 1 at lat, set k0 = (1+sin(lat))/2

Parameters:

latt - tangent point of projection, also origin of projection coord system

lont - tangent point of projection, also origin of projection coord system

latTrue - latitude of true scale in degrees north; latitude where scale factor = 1.0

Returns:

Stereographic projection

getScale

public double getScale()

Get the scale

Returns:

the scale

setScale

public void setScale(double scale)

Set the scale

Parameters:

scale - the scale

getTangentLon

public double getTangentLon()

Get the tangent longitude

Returns:

the tangent longitude

setTangentLon

public void setTangentLon(double lon)

Set the tangent longitude

Parameters:

lon - the tangent longitude

getTangentLat

public double getTangentLat()

Get the tangent latitude

Returns:

the tangent latitude

setTangentLat

public void setTangentLat(double lat)

Set the tangent latitude

Parameters:

lat - the tangent latitude

paramsToString

public java.lang.String paramsToString()

Get the parameters as a String

Specified by:

paramsToString in interface Projection

Specified by:

paramsToString in class ProjectionImpl

Returns:

the parameters as a String

crossSeam

public boolean crossSeam(ProjectionPoint pt1,
                         ProjectionPoint pt2)

Does the line between these two points cross the projection "seam".

Specified by:

crossSeam in interface Projection

Specified by:

crossSeam in class ProjectionImpl

Parameters:

pt1 - the line goes between these two points

pt2 - the line goes between these two points

Returns:

false if there is no seam

clone

public java.lang.Object clone()

Clone this projection

Overrides:

clone in class ProjectionImpl

Returns:

a clone of this.

equals

public boolean equals(java.lang.Object proj)

Returns true if this represents the same Projection as proj.

Specified by:

equals in interface Projection

Specified by:

equals in class ProjectionImpl

Parameters:

proj - projection in question

Returns:

true if this represents the same Projection as proj.

latLonToProj

public ProjectionPoint latLonToProj(LatLonPoint latLon,
                                    ProjectionPointImpl result)

Convert a LatLonPoint to projection coordinates

Specified by:

latLonToProj in interface Projection

Specified by:

latLonToProj in class ProjectionImpl

Parameters:

latLon - convert from these lat, lon coordinates

result - the object to write to

Returns:

the given result

projToLatLon

public LatLonPoint projToLatLon(ProjectionPoint world,
                                LatLonPointImpl result)

Convert projection coordinates to a LatLonPoint Note: a new object is not created on each call for the return value.

Specified by:

projToLatLon in interface Projection

Specified by:

projToLatLon in class ProjectionImpl

Parameters:

world - convert from these projection coordinates

result - the object to write to

Returns:

LatLonPoint convert to these lat/lon coordinates

latLonToProj

public float[][] latLonToProj(float[][] from,
                              float[][] to,
                              int latIndex,
                              int lonIndex)

Convert lat/lon coordinates to projection coordinates.

Overrides:

latLonToProj in class ProjectionImpl

Parameters:

from - array of lat/lon coordinates: from[2][n], where (from[latIndex][i], from[lonIndex][i]) is the (lat,lon) coordinate of the ith point

to - resulting array of projection coordinates: to[2][n] where (to[0][i], to[1][i]) is the (x,y) coordinate of the ith point

latIndex - index of lat coordinate; must be 0 or 1

lonIndex - index of lon coordinate; must be 0 or 1

Returns:

the "to" array

projToLatLon

public float[][] projToLatLon(float[][] from,
                              float[][] to)

Convert projection coordinates to lat/lon coordinate.

Overrides:

projToLatLon in class ProjectionImpl

Parameters:

from - array of projection coordinates: from[2][n], where (from[0][i], from[1][i]) is the (x, y) coordinate of the ith point

to - resulting array of lat/lon coordinates: to[2][n] where (to[0][i], to[1][i]) is the (lat, lon) coordinate of the ith point

Returns:

the "to" array

latLonToProj

public double[][] latLonToProj(double[][] from,
                               double[][] to,
                               int latIndex,
                               int lonIndex)

Convert lat/lon coordinates to projection coordinates.

Overrides:

latLonToProj in class ProjectionImpl

Parameters:

from - array of lat/lon coordinates: from[2][n], where (from[latIndex][i], from[lonIndex][i]) is the (lat,lon) coordinate of the ith point

to - resulting array of projection coordinates: to[2][n] where (to[0][i], to[1][i]) is the (x,y) coordinate of the ith point

latIndex - index of lat coordinate; must be 0 or 1

lonIndex - index of lon coordinate; must be 0 or 1

Returns:

the "to" array

projToLatLon

public double[][] projToLatLon(double[][] from,
                               double[][] to)

Convert projection coordinates to lat/lon coordinate.

Overrides:

projToLatLon in class ProjectionImpl

Parameters:

from - array of projection coordinates: from[2][n], where (from[0][i], from[1][i]) is the (x, y) coordinate of the ith point

to - resulting array of lat/lon coordinates: to[2][n] where (to[0][i], to[1][i]) is the (lat, lon) coordinate of the ith point

Returns:

the "to" array