Class Mercator
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- All Implemented Interfaces:
Serializable
,Parameterized
,LenientComparable
,MathTransform
,MathTransform2D
public class Mercator extends NormalizedProjection
Mercator Cylindrical projection (EPSG codes 9804, 9805, 1026, 1024, 1044, 9841). See the Mercator projection on MathWorld for an overview.DescriptionThe parallels and the meridians are straight lines and cross at right angles; this projection thus produces rectangular charts. The scale is true along the equator (by default) or along two parallels equidistant of the equator (if a scale factor other than 1 is used).This projection is used to represent areas close to the equator. It is also often used for maritime navigation because all the straight lines on the chart are loxodrome lines, i.e. a ship following this line would keep a constant azimuth on its compass.
This implementation handles both the 1 and 2 standard parallel cases. For Mercator (variant A) (EPSG code 9804), the line of contact is the equator. For Mercator (variant B) (EPSG code 9805) lines of contact are symmetrical about the equator.
Behavior at polesThe projection of 90°N gives positive infinity. The projection of 90°S gives negative infinity. Projection of a latitude outside the [-90 … 90]° range produces NaN.- Since:
- 0.6
- See Also:
TransverseMercator
,ObliqueMercator
, Serialized Form
Defined in the
sis-referencing
module
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Nested Class Summary
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Nested classes/interfaces inherited from class NormalizedProjection
NormalizedProjection.ParameterRole
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Field Summary
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Fields inherited from class NormalizedProjection
eccentricity, eccentricitySquared
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Constructor Summary
Constructors Constructor Description Mercator(OperationMethod method, Parameters parameters)
Creates a Mercator projection from the given parameters.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description MathTransform
createMapProjection(MathTransformFactory factory)
Returns the sequence of normalization →this
→ denormalization transforms as a whole.protected void
inverseTransform(double[] srcPts, int srcOff, double[] dstPts, int dstOff)
Converts the specified (x,y) coordinates and stores the result indstPts
(angles in radians).Matrix
transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, boolean derivate)
Converts the specified (λ,φ) coordinate (units in radians) and stores the result indstPts
(linear distance on a unit sphere).void
transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts)
Converts a list of coordinate points.-
Methods inherited from class NormalizedProjection
computeHashCode, equals, getContextualParameters, getParameterDescriptors, getParameterValues, inverse, tryConcatenate
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Methods inherited from class AbstractMathTransform2D
createTransformedShape, derivative, getSourceDimensions, getTargetDimensions, transform
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Methods inherited from class AbstractMathTransform
derivative, equals, formatTo, hashCode, isIdentity, transform, transform, transform, transform
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Methods inherited from class FormattableObject
print, toString, toString, toWKT
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Methods inherited from class Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface MathTransform
derivative, isIdentity, toWKT, transform, transform, transform, transform
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Constructor Detail
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Mercator
public Mercator(OperationMethod method, Parameters parameters)
Creates a Mercator projection from the given parameters. Themethod
argument can be the description of one of the following:- "Mercator (variant A)", also known as "Mercator (1SP)".
- "Mercator (variant B)", also known as "Mercator (2SP)".
- "Mercator (variant C)".
- "Mercator (Spherical)".
- "Popular Visualisation Pseudo Mercator".
- "Miller Cylindrical".
- Parameters:
method
- description of the projection parameters.parameters
- the parameter values of the projection to create.
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Method Detail
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createMapProjection
public MathTransform createMapProjection(MathTransformFactory factory) throws FactoryException
Returns the sequence of normalization →this
→ denormalization transforms as a whole. The transform returned by this method expects (longitude, latitude) coordinates in degrees and returns (x,y) coordinates in metres.The non-linear part of the returned transform will be
this
transform, except if the ellipsoid is spherical. In the later case,this
transform will be replaced by a simplified implementation.- Overrides:
createMapProjection
in classNormalizedProjection
- Parameters:
factory
- the factory to use for creating the transform.- Returns:
- the map projection from (λ,φ) to (x,y) coordinates.
- Throws:
FactoryException
- if an error occurred while creating a transform.- See Also:
ContextualParameters.completeTransform(MathTransformFactory, MathTransform)
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transform
public Matrix transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, boolean derivate) throws ProjectionException
Converts the specified (λ,φ) coordinate (units in radians) and stores the result indstPts
(linear distance on a unit sphere). In addition, opportunistically computes the projection derivative ifderivate
istrue
.- Specified by:
transform
in classNormalizedProjection
- Parameters:
srcPts
- the array containing the source point coordinate, as (longitude, latitude) angles in radians.srcOff
- the offset of the single coordinate to be converted in the source array.dstPts
- the array into which the converted coordinate is returned (may be the same thansrcPts
). 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 coordinate that is stored in the destination array.derivate
-true
for computing the derivative, orfalse
if not needed.- Returns:
- the matrix of the projection derivative at the given source position,
or
null
if thederivate
argument isfalse
. - Throws:
ProjectionException
- if the coordinate can not be converted.- See Also:
AbstractMathTransform.derivative(DirectPosition)
,AbstractMathTransform.transform(DirectPosition, DirectPosition)
,MathTransforms.derivativeAndTransform(MathTransform, double[], int, double[], int)
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transform
public void transform(double[] srcPts, int srcOff, double[] dstPts, int dstOff, int numPts) throws TransformException
Converts a list of coordinate points. This method performs the same calculation than abovetransform(double[], int, double[], int, boolean)
method, but is overridden for efficiency.- Specified by:
transform
in interfaceMathTransform
- Overrides:
transform
in classAbstractMathTransform
- Parameters:
srcPts
- the array containing the source point coordinates.srcOff
- the offset to the first point to be transformed in the source array.dstPts
- the array into which the transformed point coordinates are returned. May be the same thansrcPts
.dstOff
- the offset to the location of the first transformed point that is stored in the destination array.numPts
- the number of point objects to be transformed.- Throws:
TransformException
- if a point can not be converted.
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inverseTransform
protected void inverseTransform(double[] srcPts, int srcOff, double[] dstPts, int dstOff) throws ProjectionException
Converts the specified (x,y) coordinates and stores the result indstPts
(angles in radians).- Specified by:
inverseTransform
in classNormalizedProjection
- Parameters:
srcPts
- the array containing the source point coordinate, 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 coordinate is returned (may be the same thansrcPts
). 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 can not be converted.
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