Package org.apache.sis.referencing.operation.projection

Class ObliqueMercator

java.lang.Object

org.apache.sis.io.wkt.FormattableObject

org.apache.sis.referencing.operation.transform.AbstractMathTransform

org.apache.sis.referencing.operation.transform.AbstractMathTransform2D

org.apache.sis.referencing.operation.projection.NormalizedProjection

org.apache.sis.referencing.operation.projection.ObliqueMercator

All Implemented Interfaces:

Serializable, Parameterized, LenientComparable, org.opengis.referencing.operation.MathTransform, org.opengis.referencing.operation.MathTransform2D

public class ObliqueMercator
extends NormalizedProjection

Oblique Mercator projection (EPSG codes 9812, 9815). The Oblique Mercator projection can be seen as a generalization of Mercator and TransverseMercator projections when the central line is not along the equator or a meridian, respectively. This class covers also the Rectified Skew Orthomorphic (RSO) case.

There is different ways to specify the projection parameters:

• Variant A (EPSG:9812) uses false easting/northing defined at the natural origin of the coordinate system.
• Variant B (EPSG:9815) uses false easting/northing defined at the projection center.
• ESRI "Two Points" variant defines the central line with two points instead of with an azimuth angle.

Azimuth values of 0 and ±90 degrees are allowed, but for such cases the Mercator and TransverseMercator projections should be preferred, both for performance and accuracy reasons.

Since:

1.0

Version:

1.2

Author:

Rueben Schulz (UBC), Martin Desruisseaux (Geomatys), Rémi Maréchal (Geomatys), Emmanuel Giasson (Thales)

See Also:

• Mercator
• TransverseMercator
• Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.sis.referencing.operation.projection.NormalizedProjection

NormalizedProjection.ParameterRole

Field Summary

Fields inherited from class org.apache.sis.referencing.operation.projection.NormalizedProjection

eccentricity, eccentricitySquared

Fields inherited from class org.apache.sis.referencing.operation.transform.AbstractMathTransform2D

DIMENSION

Constructor Summary

Constructors

Constructor	Description
ObliqueMercator(org.opengis.referencing.operation.OperationMethod method, Parameters parameters)	Creates an Oblique Mercator projection from the given parameters.

Method Summary

Modifier and Type	Method	Description
protected void	inverseTransform(double[] srcPts, int srcOff, double[] dstPts, int dstOff)	Converts the specified (x,y) coordinates and stores the result in dstPts (angles in radians).
org.opengis.referencing.operation.Matrix	transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, boolean derivate)	Projects the specified (λ,φ) coordinates (units in radians) and stores the result in dstPts.

Methods inherited from class org.apache.sis.referencing.operation.projection.NormalizedProjection

computeHashCode, createMapProjection, equals, getContextualParameters, getParameterDescriptors, getParameterValues, inverse, tryConcatenate

Methods inherited from class org.apache.sis.referencing.operation.transform.AbstractMathTransform2D

createTransformedShape, derivative, getSourceDimensions, getTargetDimensions, transform

Methods inherited from class org.apache.sis.referencing.operation.transform.AbstractMathTransform

derivative, equals, formatTo, getDomain, hashCode, isIdentity, transform, transform, transform, transform, transform

Methods inherited from class org.apache.sis.io.wkt.FormattableObject

print, toString, toString, toWKT

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.opengis.referencing.operation.MathTransform

derivative, isIdentity, toWKT, transform, transform, transform, transform, transform

Constructor Details

ObliqueMercator

public ObliqueMercator(org.opengis.referencing.operation.OperationMethod method,
 Parameters parameters)

Creates an Oblique Mercator projection from the given parameters. The method argument can be the description of one of the following:

• "Hotine Oblique Mercator (variant A)".
• "Hotine Oblique Mercator (variant B)".
• "Hotine Oblique Mercator two point center" (from ESRI).
• "Hotine Oblique Mercator two point natural origin" (from ESRI).
• "Rectified Skew Orthomorphic".

Parameters:

method - description of the projection parameters.

parameters - the parameter values of the projection to create.

Method Details

transform

public org.opengis.referencing.operation.Matrix transform(double[] srcPts,
 int srcOff,
 double[] dstPts,
 int dstOff,
 boolean derivate)
                                                   throws ProjectionException

Projects the specified (λ,φ) coordinates (units in radians) and stores the result in dstPts. In addition, opportunistically computes the projection derivative if derivate is true. The results must be multiplied by the denormalization matrix before to get linear distances.

Specified by:

transform in class NormalizedProjection

Parameters:

srcPts - the array containing the source point coordinates, as (longitude, latitude) angles in radians.

srcOff - the offset of the single coordinate tuple to be converted in the source array.

dstPts - the array into which the converted coordinates is returned (may be the same than srcPts). Coordinates will be expressed in a dimensionless unit, as a linear distance on a unit sphere or ellipse.

dstOff - the offset of the location of the converted coordinates that is stored in the destination array.

derivate - true for computing the derivative, or false if not needed.

Returns:

the matrix of the projection derivative at the given source position, or null if the derivate argument is false.

Throws:

ProjectionException - if the coordinates cannot be converted.

See Also:

• AbstractMathTransform.derivative(DirectPosition)
• AbstractMathTransform.transform(DirectPosition, DirectPosition)
• MathTransforms.derivativeAndTransform(MathTransform, double[], int, double[], int)

inverseTransform

protected void inverseTransform(double[] srcPts,
 int srcOff,
 double[] dstPts,
 int dstOff)
                         throws ProjectionException

Converts the specified (x,y) coordinates and stores the result in dstPts (angles in radians).

Specified by:

inverseTransform in class NormalizedProjection

Parameters:

srcPts - the array containing the source point coordinates, as linear distance on a unit sphere or ellipse.

srcOff - the offset of the point to be converted in the source array.

dstPts - the array into which the converted point coordinates is returned (may be the same than srcPts). Coordinates will be (longitude, latitude) angles in radians.

dstOff - the offset of the location of the converted point that is stored in the destination array.

Throws:

ProjectionException - if the point cannot be converted.