NetTopologySuite.Geometries.PrecisionModel Class Reference

Specifies the precision model of the Coordinates in a Geometry. In other words, specifies the grid of allowable points for all Geometrys. More...

Inheritance diagram for NetTopologySuite.Geometries.PrecisionModel:

Public Member Functions
	PrecisionModel ()
	Creates a PrecisionModel with a default precision of Floating. More...
	PrecisionModel (PrecisionModels modelType)
	Creates a PrecisionModel that specifies an explicit precision model type. If the model type is Fixed the scale factor will default to 1. More...
	PrecisionModel (double scale, double offsetX, double offsetY)
	Creates a PrecisionModel that specifies Fixed precision. Fixed-precision coordinates are represented as precise internal coordinates, which are rounded to the grid defined by the scale factor. More...
	PrecisionModel (double scale)
	Creates a PrecisionModel that specifies Fixed precision. Fixed-precision coordinates are represented as precise internal coordinates, which are rounded to the grid defined by the scale factor. More...
	PrecisionModel (PrecisionModel pm)
	Copy constructor to create a new PrecisionModel from an existing one. More...
override int	GetHashCode ()
	Return HashCode. More...
void	ToInternal (Coordinate cexternal, Coordinate cinternal)
	Sets internal to the precise representation of external. More...
Coordinate	ToInternal (Coordinate cexternal)
	Returns the precise representation of external. More...
Coordinate	ToExternal (Coordinate cinternal)
	Returns the external representation of internal. More...
void	ToExternal (Coordinate cinternal, Coordinate cexternal)
	Sets external to the external representation of internal. More...
double	MakePrecise (double val)
	Rounds a numeric value to the PrecisionModel grid. Symmetric Arithmetic Rounding is used, to provide uniform rounding behaviour no matter where the number is on the number line. More...
void	MakePrecise (Coordinate coord)
	Rounds a Coordinate to the PrecisionModel grid. More...
override string	ToString ()
override bool	Equals (object other)
bool	Equals (IPrecisionModel otherPrecisionModel)
int	CompareTo (object o)
	Compares this PrecisionModel object with the specified object for order. A PrecisionModel is greater than another if it provides greater precision. The comparison is based on the value returned by the {getMaximumSignificantDigits) method. This comparison is not strictly accurate when comparing floating precision models to fixed models; however, it is correct when both models are either floating or fixed. More...
int	CompareTo (IPrecisionModel other)

Static Public Member Functions
static IPrecisionModel	MostPrecise (IPrecisionModel pm1, IPrecisionModel pm2)
	Determines which of two IPrecisionModels is the most precise /summary> Parameters pm1 A precision model pm2 A precision model Returns The PrecisionModel which is most precise
static bool	operator== (PrecisionModel obj1, PrecisionModel obj2)
static bool	operator!= (PrecisionModel obj1, PrecisionModel obj2)

Public Attributes
const double	MaximumPreciseValue = 9007199254740992.0
	The maximum precise value representable in a double. Since IEE754 double-precision numbers allow 53 bits of mantissa, the value is equal to 2^53 - 1. This provides almost 16 decimal digits of precision. More...

Properties
bool	IsFloating [get]
	Tests whether the precision model supports floating point. More...
int	MaximumSignificantDigits [get]
	Returns the maximum number of significant digits provided by this precision model. Intended for use by routines which need to print out precise values. More...
double	Scale [get, set]
	Returns the scale factor used to specify a fixed precision model. More...
PrecisionModels	PrecisionModelType [get]
	Gets the type of this PrecisionModel. More...
double	OffsetX [get]
	Returns the x-offset used to obtain a precise coordinate. More...
double	OffsetY [get]
	Returns the y-offset used to obtain a precise coordinate. More...

Detailed Description

Specifies the precision model of the Coordinates in a Geometry. In other words, specifies the grid of allowable points for all Geometrys.

The MakePrecise method allows rounding a coordinate to a "precise" value; that is, one whose precision is known exactly. Coordinates are assumed to be precise in geometries. That is, the coordinates are assumed to be rounded to the precision model given for the point. NTS input routines automatically round coordinates to the precision model before creating Geometries. All internal operations assume that coordinates are rounded to the precision model. Constructive methods (such as bool operations) always round computed coordinates to the appropriate precision model. Currently three types of precision model are supported:

Floating: represents full double precision floating point. This is the default precision model used in NTS FloatingSingle: represents single precision floating point. Fixed: represents a model with a fixed number of decimal places.

A Fixed Precision Model is specified by a scale factor. The scale factor specifies the size of the grid which numbers are rounded to. Input coordinates are mapped to fixed coordinates according to the following equations:

• jtsPt.x = round( (inputPt.x * scale ) / scale
• jtsPt.y = round( (inputPt.y * scale ) / scale

For example, to specify 3 decimal places of precision, use a scale factor of 1000. To specify -3 decimal places of precision (i.e. rounding to the nearest 1000), use a scale factor of 0.001.

Coordinates are represented internally as Java double-precision values. Since .NET uses the IEEE-394 floating point standard, this provides 53 bits of precision. (Thus the maximum precisely representable integer is 9,007,199,254,740,992 - or almost 16 decimal digits of precision).

NTS binary methods currently do not handle inputs which have different precision models. The precision model of any constructed geometric value is undefined.

Constructor & Destructor Documentation

NetTopologySuite.Geometries.PrecisionModel.PrecisionModel

(

)

Creates a PrecisionModel with a default precision of Floating.

NetTopologySuite.Geometries.PrecisionModel.PrecisionModel

(

PrecisionModels

modelType

)

Creates a PrecisionModel that specifies an explicit precision model type. If the model type is Fixed the scale factor will default to 1.

Parameters

modelType

The type of the precision model.

NetTopologySuite.Geometries.PrecisionModel.PrecisionModel	(	double	scale,
		double	offsetX,
		double	offsetY
	)

Creates a PrecisionModel that specifies Fixed precision. Fixed-precision coordinates are represented as precise internal coordinates, which are rounded to the grid defined by the scale factor.

Parameters

scale	Amount by which to multiply a coordinate after subtracting the offset, to obtain a precise coordinate
offsetX	Not used.
offsetY	Not used.

NetTopologySuite.Geometries.PrecisionModel.PrecisionModel

(

double

scale

)

Creates a PrecisionModel that specifies Fixed precision. Fixed-precision coordinates are represented as precise internal coordinates, which are rounded to the grid defined by the scale factor.

Parameters

scale

Amount by which to multiply a coordinate after subtracting the offset, to obtain a precise coordinate.

NetTopologySuite.Geometries.PrecisionModel.PrecisionModel

(

PrecisionModel

pm

)

Copy constructor to create a new PrecisionModel from an existing one.

Parameters

pm

Member Function Documentation

int NetTopologySuite.Geometries.PrecisionModel.CompareTo

(

object

o

)

Compares this PrecisionModel object with the specified object for order. A PrecisionModel is greater than another if it provides greater precision. The comparison is based on the value returned by the {getMaximumSignificantDigits) method. This comparison is not strictly accurate when comparing floating precision models to fixed models; however, it is correct when both models are either floating or fixed.

Parameters

o	The PrecisionModel with which this PrecisionModel is being compared.

Returns

A negative integer, zero, or a positive integer as this PrecisionModel is less than, equal to, or greater than the specified PrecisionModel.

int NetTopologySuite.Geometries.PrecisionModel.CompareTo

(

IPrecisionModel

other

)

Parameters

other

Returns

override bool NetTopologySuite.Geometries.PrecisionModel.Equals

(

object

other

)

Parameters

other

Returns

bool NetTopologySuite.Geometries.PrecisionModel.Equals

(

IPrecisionModel

otherPrecisionModel

)

Parameters

otherPrecisionModel

Returns

override int NetTopologySuite.Geometries.PrecisionModel.GetHashCode

(

)

Return HashCode.

double NetTopologySuite.Geometries.PrecisionModel.MakePrecise

(

double

val

)

Rounds a numeric value to the PrecisionModel grid. Symmetric Arithmetic Rounding is used, to provide uniform rounding behaviour no matter where the number is on the number line.

This method has no effect on NaN values

Parameters

val

void NetTopologySuite.Geometries.PrecisionModel.MakePrecise

(

Coordinate

coord

)

Rounds a Coordinate to the PrecisionModel grid.

Parameters

coord

static bool NetTopologySuite.Geometries.PrecisionModel.operator!= ( PrecisionModel  obj1, PrecisionModel  obj2  )

static

Parameters

obj1
obj2

Returns

static bool NetTopologySuite.Geometries.PrecisionModel.operator== ( PrecisionModel  obj1, PrecisionModel  obj2  )

static

Parameters

obj1
obj2

Returns

Coordinate NetTopologySuite.Geometries.PrecisionModel.ToExternal

(

Coordinate

cinternal

)

Returns the external representation of internal.

Parameters

cinternal

The original coordinate.

Returns

The coordinate whose values will be changed to the external representation of internal.

void NetTopologySuite.Geometries.PrecisionModel.ToExternal	(	Coordinate	cinternal,
		Coordinate	cexternal
	)

Sets external to the external representation of internal.

Parameters

cinternal	The original coordinate.
cexternal	The coordinate whose values will be changed to the external representation of internal.

void NetTopologySuite.Geometries.PrecisionModel.ToInternal	(	Coordinate	cexternal,
		Coordinate	cinternal
	)

Sets internal to the precise representation of external.

Parameters

cexternal	The original coordinate.
cinternal	The coordinate whose values will be changed to the precise representation of external.

Coordinate NetTopologySuite.Geometries.PrecisionModel.ToInternal

(

Coordinate

cexternal

)

Returns the precise representation of external.

Parameters

cexternal

The original coordinate.

Returns

The coordinate whose values will be changed to the precise representation of external

override string NetTopologySuite.Geometries.PrecisionModel.ToString

(

)

Returns

Member Data Documentation

const double NetTopologySuite.Geometries.PrecisionModel.MaximumPreciseValue = 9007199254740992.0

The maximum precise value representable in a double. Since IEE754 double-precision numbers allow 53 bits of mantissa, the value is equal to 2^53 - 1. This provides almost 16 decimal digits of precision.

Property Documentation

bool NetTopologySuite.Geometries.PrecisionModel.IsFloating

get

Tests whether the precision model supports floating point.

Returns

true if the precision model supports floating point.

int NetTopologySuite.Geometries.PrecisionModel.MaximumSignificantDigits

get

Returns the maximum number of significant digits provided by this precision model. Intended for use by routines which need to print out precise values.

Returns

The maximum number of decimal places provided by this precision model.

double NetTopologySuite.Geometries.PrecisionModel.OffsetX

get

Returns the x-offset used to obtain a precise coordinate.

Returns

The amount by which to subtract the x-coordinate before multiplying by the scale.

double NetTopologySuite.Geometries.PrecisionModel.OffsetY

get

Returns the y-offset used to obtain a precise coordinate.

Returns

The amount by which to subtract the y-coordinate before multiplying by the scale

PrecisionModels NetTopologySuite.Geometries.PrecisionModel.PrecisionModelType

get

Gets the type of this PrecisionModel.

Returns

double NetTopologySuite.Geometries.PrecisionModel.Scale

getset

Returns the scale factor used to specify a fixed precision model.

The number of decimal places of precision is equal to the base-10 logarithm of the scale factor. Non-integral and negative scale factors are supported. Negative scale factors indicate that the places of precision is to the left of the decimal point.

Returns

The scale factor for the fixed precision model

---

The documentation for this class was generated from the following file:

• NetTopologySuite/NetTopologySuite/Geometries/PrecisionModel.cs