org.gicentre.utils.spatial

Class ObliqueMercator

java.lang.Object

org.gicentre.utils.spatial.ObliqueMercator

All Implemented Interfaces:

MapProjection

public class ObliqueMercator
extends java.lang.Object
implements MapProjection

Class for representing Oblique Mercator projections. Includes forward and inverse transforms from and to longitude/latitude. Uses transformation equations from Snyder (1987) Atlas of Map Projections summarised at this Hotine Oblique Mercator page.

Version:

3.4, 5th February, 2016.

Author:

Jo Wood, giCentre, City University London.

Field Summary

Fields

Modifier and Type	Field and Description
static int	FROM_LAT_LONG Indicates a transformation from longitude/latitude
static int	TO_LAT_LONG Indicates a transformation to longitude/latitude

Constructor Summary

Constructors

Constructor and Description
ObliqueMercator(Ellipsoid ellipsoid) Initialises the Oblique Mercator converter with the given ellipsoid.

Method Summary

Modifier and Type	Method and Description
boolean	doInterpolation() Indicates whether the transformation should use nearest neighbour (false) or some interpolator (true).
java.lang.String	getDescription() Provides a general description of the transformation.
Ellipsoid	getEllipsoid() Reports the ellipsoid used in the transformation.
processing.core.PVector	invTransformCoords(processing.core.PVector p) Performs an inverse Oblique Mercator to lat/long transform on the given location.
processing.core.PVector	latLongToObliqueMercator(processing.core.PVector p) Converts the given (lat,lng) coordinates into an oblique Mercator location.
processing.core.PVector	obliqueMercatorToLatLong(processing.core.PVector p) Converts the given Oblique Mercator coordinates into a longitude/latitude location.
void	setInterpolation(boolean doInterpolation) Sets whether the transformation should use nearest neighbour (false) or some interpolator (true).
processing.core.PVector	transformCoords(processing.core.PVector p) Performs a forward longitude/latitude to Oblique Mercator transform on the given location.

Methods inherited from class java.lang.Object

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

Field Detail

FROM_LAT_LONG

public static final int FROM_LAT_LONG

Indicates a transformation from longitude/latitude

See Also:

Constant Field Values

TO_LAT_LONG

public static final int TO_LAT_LONG

Indicates a transformation to longitude/latitude

See Also:

Constant Field Values

Constructor Detail

ObliqueMercator

public ObliqueMercator(Ellipsoid ellipsoid)

Initialises the Oblique Mercator converter with the given ellipsoid. The forward transformation will be from Lat/long to Oblique Merctor.

Parameters:

ellipsoid - to use in projection.

Method Detail

transformCoords

public processing.core.PVector transformCoords(processing.core.PVector p)

Performs a forward longitude/latitude to Oblique Mercator transform on the given location.

Specified by:

transformCoords in interface MapProjection

Parameters:

p - point coordinates to transform.

Returns:

Transformed footprint.

invTransformCoords

public processing.core.PVector invTransformCoords(processing.core.PVector p)

Performs an inverse Oblique Mercator to lat/long transform on the given location.

Specified by:

invTransformCoords in interface MapProjection

Parameters:

p - Point coordinates to transform

Returns:

Transformed footprint.

getDescription

public java.lang.String getDescription()

Provides a general description of the transformation.

Specified by:

getDescription in interface MapProjection

Returns:

Description of the transformation.

doInterpolation

public boolean doInterpolation()

Indicates whether the transformation should use nearest neighbour (false) or some interpolator (true).

Returns:

True if transformation should perform some local interpolation.

setInterpolation

public void setInterpolation(boolean doInterpolation)

Sets whether the transformation should use nearest neighbour (false) or some interpolator (true).

Parameters:

doInterpolation - True if transformation should perform some local interpolation.

latLongToObliqueMercator

public processing.core.PVector latLongToObliqueMercator(processing.core.PVector p)

Converts the given (lat,lng) coordinates into an oblique Mercator location. Longitude/latitude should be in decimal degrees with positive North and positive East.

Parameters:

p - Longitude/latitude point. Longitude varies within +-180 degrees, latitude within +-90 degrees.

Returns:

Oblique Mercator location.

obliqueMercatorToLatLong

public processing.core.PVector obliqueMercatorToLatLong(processing.core.PVector p)

Converts the given Oblique Mercator coordinates into a longitude/latitude location. Longitude/latitude will be in decimal degrees with positive North and negative East.

Parameters:

p - Location of point as an easting and northing in the Oblique Mercator projection (metres from local origin).

Returns:

Longitude/latitude location.

getEllipsoid

public Ellipsoid getEllipsoid()

Reports the ellipsoid used in the transformation.

Returns:

Ellipsoid used in the Oblique Mercator transformation.