geos::geom::Envelope Class Reference

An Envelope defines a rectangulare region of the 2D coordinate plane. More...

#include <geos.h>

Public Types
typedef std::unique_ptr< Envelope >	Ptr

Public Member Functions
	Envelope ()
	Creates a null Envelope. More...
	Envelope (double x1, double x2, double y1, double y2)
	Creates an Envelope for a region defined by maximum and minimum values. More...
	Envelope (const Coordinate &p1, const Coordinate &p2)
	Creates an Envelope for a region defined by two Coordinates. More...
	Envelope (const Coordinate &p)
	Creates an Envelope for a region defined by a single Coordinate. More...
	Envelope (const Envelope &env)
	Copy constructor. More...
Envelope &	operator= (const Envelope &e)
	Assignment operator. More...
	Envelope (const std::string &str)
	Create an Envelope from an Envelope string representation produced by Envelope::toString() More...
bool	intersects (const Coordinate &a, const Coordinate &b) const
	Check if the extent defined by two extremal points intersects the extent of this Envelope. More...
void	init (void)
	Initialize to a null Envelope. More...
void	init (double x1, double x2, double y1, double y2)
	Initialize an Envelope for a region defined by maximum and minimum values. More...
void	init (const Coordinate &p1, const Coordinate &p2)
	Initialize an Envelope to a region defined by two Coordinates. More...
void	init (const Coordinate &p)
	Initialize an Envelope to a region defined by a single Coordinate. More...
void	setToNull (void)
	Makes this Envelope a "null" envelope, that is, the envelope of the empty geometry. More...
bool	isNull (void) const
	Returns true if this Envelope is a "null" envelope. More...
double	getWidth (void) const
	Returns the difference between the maximum and minimum x values. More...
double	getHeight (void) const
	Returns the difference between the maximum and minimum y values. More...
double	getArea () const
	Gets the area of this envelope. More...
double	getMaxY () const
	Returns the Envelope maximum y-value. min y > max y indicates that this is a null Envelope. More...
double	getMaxX () const
	Returns the Envelope maximum x-value. min x > max x indicates that this is a null Envelope. More...
double	getMinY () const
	Returns the Envelope minimum y-value. min y > max y indicates that this is a null Envelope. More...
double	getMinX () const
	Returns the Envelope minimum x-value. min x > max x indicates that this is a null Envelope. More...
bool	centre (Coordinate &centre) const
	Computes the coordinate of the centre of this envelope (as long as it is non-null). More...
bool	intersection (const Envelope &env, Envelope &result) const
	Computes the intersection of two Envelopes. More...
void	translate (double transX, double transY)
	Translates this envelope by given amounts in the X and Y direction. More...
void	expandBy (double deltaX, double deltaY)
	Expands this envelope by a given distance in all directions. Both positive and negative distances are supported. More...
void	expandBy (double p_distance)
	Expands this envelope by a given distance in all directions. More...
void	expandToInclude (const Coordinate &p)
	Enlarges the boundary of the Envelope so that it contains p. Does nothing if p is already on or within the boundaries. More...
void	expandToInclude (double x, double y)
	Enlarges the boundary of the Envelope so that it contains (x,y). More...
void	expandToInclude (const Envelope *other)
	Enlarges the boundary of the Envelope so that it contains other. More...
void	expandToInclude (const Envelope &other)
bool	contains (const Envelope &other) const
	Tests if the Envelope other lies wholly inside this Envelope (inclusive of the boundary). More...
bool	contains (const Envelope *other) const
bool	contains (const Coordinate &p) const
	Returns true if the given point lies in or on the envelope. More...
bool	contains (double x, double y) const
	Returns true if the given point lies in or on the envelope. More...
bool	intersects (const Coordinate &p) const
	Check if the point p intersects (lies inside) the region of this Envelope. More...
bool	intersects (double x, double y) const
	Check if the point (x, y) intersects (lies inside) the region of this Envelope. More...
bool	intersects (const Envelope *other) const
	Check if the region defined by other Envelope intersects the region of this Envelope. More...
bool	intersects (const Envelope &other) const
bool	disjoint (const Envelope *other) const
bool	disjoint (const Envelope &other) const
bool	covers (double x, double y) const
	Tests if the given point lies in or on the envelope. More...
bool	covers (const Coordinate *p) const
	Tests if the given point lies in or on the envelope. More...
bool	covers (const Envelope &other) const
	Tests if the Envelope other lies wholly inside this Envelope (inclusive of the boundary). More...
bool	covers (const Envelope *other) const
bool	equals (const Envelope *other) const
	Returns true if the Envelope other spatially equals this Envelope. More...
std::string	toString (void) const
	Returns a string of the form Env[minx:maxx,miny:maxy]. More...
double	distance (const Envelope &env) const
	Computes the distance between this and another Envelope. More...
double	distanceSquared (const Envelope &env) const
	Computes the square of the distance between this and another Envelope. More...
size_t	hashCode () const

Static Public Member Functions
static bool	intersects (const Coordinate &p1, const Coordinate &p2, const Coordinate &q)
	Test the point q to see whether it intersects the Envelope defined by p1-p2. More...
static bool	intersects (const Coordinate &p1, const Coordinate &p2, const Coordinate &q1, const Coordinate &q2)
	Test the envelope defined by p1-p2 for intersection with the envelope defined by q1-q2. More...
static double	distanceToCoordinate (const Coordinate &c, const Coordinate &p1, const Coordinate &p2)
	Computes the distance between one Coordinate and an Envelope defined by two other Coordinates. The order of the Coordinates used to define the envelope is not significant. More...
static double	distanceSquaredToCoordinate (const Coordinate &c, const Coordinate &p1, const Coordinate &p2)
	Computes the squared distance between one Coordinate and an Envelope defined by two other Coordinates. The order of the Coordinates used to define the envelope is not significant. More...

Private Member Functions
std::vector< std::string >	split (const std::string &str, const std::string &delimiters=" ")
	Splits a string into parts based on the supplied delimiters. More...

Static Private Member Functions
static double	distance (double x0, double y0, double x1, double y1)

Private Attributes
double	minx
	the minimum x-coordinate More...
double	maxx
	the maximum x-coordinate More...
double	miny
	the minimum y-coordinate More...
double	maxy
	the maximum y-coordinate More...

Friends
std::ostream &	operator<< (std::ostream &os, const Envelope &o)
	Output operator. More...

Detailed Description

An Envelope defines a rectangulare region of the 2D coordinate plane.

It is often used to represent the bounding box of a Geometry, e.g. the minimum and maximum x and y values of the Coordinates.

Note that Envelopes support infinite or half-infinite regions, by using the values of Double_POSITIVE_INFINITY and Double_NEGATIVE_INFINITY.

When Envelope objects are created or initialized, the supplies extent values are automatically sorted into the correct order.

Definition at line 58 of file Envelope.h.

Member Typedef Documentation

typedef std::unique_ptr<Envelope> geos::geom::Envelope::Ptr

Definition at line 64 of file Envelope.h.

Constructor & Destructor Documentation

geos::geom::Envelope::Envelope

(

)

Creates a null Envelope.

geos::geom::Envelope::Envelope	(	double	x1,
		double	x2,
		double	y1,
		double	y2
	)

Creates an Envelope for a region defined by maximum and minimum values.

Parameters

x1	the first x-value
x2	the second x-value
y1	the first y-value
y2	the second y-value

geos::geom::Envelope::Envelope	(	const Coordinate &	p1,
		const Coordinate &	p2
	)

Creates an Envelope for a region defined by two Coordinates.

Parameters

p1	the first Coordinate
p2	the second Coordinate

geos::geom::Envelope::Envelope

(

const Coordinate &

p

)

Creates an Envelope for a region defined by a single Coordinate.

Parameters

p	the Coordinate

geos::geom::Envelope::Envelope

(

const Envelope &

env

)

Copy constructor.

geos::geom::Envelope::Envelope

(

const std::string &

str

)

Create an Envelope from an Envelope string representation produced by Envelope::toString()

Member Function Documentation

bool geos::geom::Envelope::centre

(

Coordinate &

centre

)

const

Computes the coordinate of the centre of this envelope (as long as it is non-null).

Parameters

centre

The coordinate to write results into

Returns

false if the center could not be found (null envelope).

bool geos::geom::Envelope::contains ( const Envelope &  other ) const

inline

Tests if the Envelope other lies wholly inside this Envelope (inclusive of the boundary).

Note that this is not the same definition as the SFS contains, which would exclude the envelope boundary.

Parameters

other

the Envelope to check

Returns

true if other is contained in this Envelope

See also

covers(Envelope)

Definition at line 335 of file Envelope.h.

bool geos::geom::Envelope::contains ( const Envelope *  other ) const

inline

Definition at line 341 of file Envelope.h.

bool geos::geom::Envelope::contains ( const Coordinate &  p ) const

inline

Returns true if the given point lies in or on the envelope.

Parameters

p	the point which this Envelope is being checked for containing

Returns

true if the point lies in the interior or on the boundary of this Envelope.

Definition at line 354 of file Envelope.h.

References geos::geom::Coordinate::x, and geos::geom::Coordinate::y.

bool geos::geom::Envelope::contains ( double  x, double  y  ) const

inline

Returns true if the given point lies in or on the envelope.

Parameters

x	the x-coordinate of the point which this Envelope is being checked for containing
y	the y-coordinate of the point which this Envelope is being checked for containing

Returns

true if (x, y) lies in the interior or on the boundary of this Envelope.

Definition at line 370 of file Envelope.h.

bool geos::geom::Envelope::covers	(	double	x,
		double	y
	)		const

Tests if the given point lies in or on the envelope.

Parameters

x	the x-coordinate of the point which this Envelope is being checked for containing
y	the y-coordinate of the point which this Envelope is being checked for containing

Returns

true if (x, y) lies in the interior or on the boundary of this Envelope.

bool geos::geom::Envelope::covers

(

const Coordinate *

p

)

const

Tests if the given point lies in or on the envelope.

Parameters

p	the point which this Envelope is being checked for containing

Returns

true if the point lies in the interior or on the boundary of this Envelope.

bool geos::geom::Envelope::covers

(

const Envelope &

other

)

const

Tests if the Envelope other lies wholly inside this Envelope (inclusive of the boundary).

Parameters

other

the Envelope to check

Returns

true if this Envelope covers the other

bool geos::geom::Envelope::covers ( const Envelope *  other ) const

inline

Definition at line 439 of file Envelope.h.

bool geos::geom::Envelope::disjoint

(

const Envelope *

other

)

const

Tests if the region defined by other is disjoint from the region of this Envelope

Parameters

other

the Envelope being checked for disjointness

Returns

true if the Envelopes are disjoint

bool geos::geom::Envelope::disjoint

(

const Envelope &

other

)

const

double geos::geom::Envelope::distance

(

const Envelope &

env

)

const

Computes the distance between this and another Envelope.

The distance between overlapping Envelopes is 0. Otherwise, the distance is the Euclidean distance between the closest points.

static double geos::geom::Envelope::distance ( double  x0, double  y0, double  x1, double  y1  )

staticprivate

double geos::geom::Envelope::distanceSquared

(

const Envelope &

env

)

const

Computes the square of the distance between this and another Envelope.

The distance between overlapping Envelopes is 0. Otherwise, the distance is the Euclidean distance between the closest points.

static double geos::geom::Envelope::distanceSquaredToCoordinate ( const Coordinate &  c, const Coordinate &  p1, const Coordinate &  p2  )

static

Computes the squared distance between one Coordinate and an Envelope defined by two other Coordinates. The order of the Coordinates used to define the envelope is not significant.

Parameters

c	the coordinate to from which distance should be found
p1	first coordinate defining an envelope
p2	second coordinate defining an envelope.

static double geos::geom::Envelope::distanceToCoordinate ( const Coordinate &  c, const Coordinate &  p1, const Coordinate &  p2  )

static

Computes the distance between one Coordinate and an Envelope defined by two other Coordinates. The order of the Coordinates used to define the envelope is not significant.

Parameters

c	the coordinate to from which distance should be found
p1	first coordinate defining an envelope
p2	second coordinate defining an envelope.

bool geos::geom::Envelope::equals

(

const Envelope *

other

)

const

Returns true if the Envelope other spatially equals this Envelope.

Parameters

other

the Envelope which this Envelope is being checked for equality

Returns

true if this and other Envelope objects are spatially equal

void geos::geom::Envelope::expandBy	(	double	deltaX,
		double	deltaY
	)

Expands this envelope by a given distance in all directions. Both positive and negative distances are supported.

Parameters

deltaX	the distance to expand the envelope along the X axis
deltaY	the distance to expand the envelope along the Y axis

void geos::geom::Envelope::expandBy ( double  p_distance )

inline

Expands this envelope by a given distance in all directions.

Both positive and negative distances are supported.

Parameters

p_distance

the distance to expand the envelope

Definition at line 286 of file Envelope.h.

void geos::geom::Envelope::expandToInclude

(

const Coordinate &

p

)

Enlarges the boundary of the Envelope so that it contains p. Does nothing if p is already on or within the boundaries.

Parameters

p	the Coordinate to include

void geos::geom::Envelope::expandToInclude	(	double	x,
		double	y
	)

Enlarges the boundary of the Envelope so that it contains (x,y).

Does nothing if (x,y) is already on or within the boundaries.

Parameters

x	the value to lower the minimum x to or to raise the maximum x to
y	the value to lower the minimum y to or to raise the maximum y to

void geos::geom::Envelope::expandToInclude

(

const Envelope *

other

)

Enlarges the boundary of the Envelope so that it contains other.

Does nothing if other is wholly on or within the boundaries.

Parameters

other

the Envelope to merge with

void geos::geom::Envelope::expandToInclude

(

const Envelope &

other

)

double geos::geom::Envelope::getArea ( ) const

inline

Gets the area of this envelope.

Returns

the area of the envelope

0.0 if the envelope is null

Definition at line 212 of file Envelope.h.

Referenced by geos::index::strtree::SimpleSTRnode::area().

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double geos::geom::Envelope::getHeight

(

void

)

const

Returns the difference between the maximum and minimum y values.

Returns

max y - min y, or 0 if this is a null Envelope

double geos::geom::Envelope::getMaxX

(

)

const

Returns the Envelope maximum x-value. min x > max x indicates that this is a null Envelope.

double geos::geom::Envelope::getMaxY

(

)

const

Returns the Envelope maximum y-value. min y > max y indicates that this is a null Envelope.

Referenced by geos::index::strtree::STRtree::centreY().

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double geos::geom::Envelope::getMinX

(

)

const

Returns the Envelope minimum x-value. min x > max x indicates that this is a null Envelope.

double geos::geom::Envelope::getMinY

(

)

const

Returns the Envelope minimum y-value. min y > max y indicates that this is a null Envelope.

Referenced by geos::index::strtree::STRtree::centreY().

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double geos::geom::Envelope::getWidth

(

void

)

const

Returns the difference between the maximum and minimum x values.

Returns

max x - min x, or 0 if this is a null Envelope

size_t geos::geom::Envelope::hashCode

(

)

const

void geos::geom::Envelope::init

(

void

)

Initialize to a null Envelope.

void geos::geom::Envelope::init	(	double	x1,
		double	x2,
		double	y1,
		double	y2
	)

Initialize an Envelope for a region defined by maximum and minimum values.

Parameters

x1	the first x-value
x2	the second x-value
y1	the first y-value
y2	the second y-value

void geos::geom::Envelope::init	(	const Coordinate &	p1,
		const Coordinate &	p2
	)

Initialize an Envelope to a region defined by two Coordinates.

Parameters

p1	the first Coordinate
p2	the second Coordinate

void geos::geom::Envelope::init

(

const Coordinate &

p

)

Initialize an Envelope to a region defined by a single Coordinate.

Parameters

p	the Coordinate

bool geos::geom::Envelope::intersection	(	const Envelope &	env,
		Envelope &	result
	)		const

Computes the intersection of two Envelopes.

Parameters

env	the envelope to intersect with
result	the envelope representing the intersection of the envelopes (this will be the null envelope if either argument is null, or they do not intersect)

Returns

false if not intersection is found

static bool geos::geom::Envelope::intersects ( const Coordinate &  p1, const Coordinate &  p2, const Coordinate &  q  )

static

Test the point q to see whether it intersects the Envelope defined by p1-p2.

Parameters

p1	one extremal point of the envelope
p2	another extremal point of the envelope
q	the point to test for intersection

Returns

true if q intersects the envelope p1-p2

static bool geos::geom::Envelope::intersects ( const Coordinate &  p1, const Coordinate &  p2, const Coordinate &  q1, const Coordinate &  q2  )

static

Test the envelope defined by p1-p2 for intersection with the envelope defined by q1-q2.

Parameters

p1	one extremal point of the envelope P
p2	another extremal point of the envelope P
q1	one extremal point of the envelope Q
q2	another extremal point of the envelope Q

Returns

true if Q intersects P

bool geos::geom::Envelope::intersects	(	const Coordinate &	a,
		const Coordinate &	b
	)		const

Check if the extent defined by two extremal points intersects the extent of this Envelope.

Parameters

a	a point
b	another point

Returns

true if the extents intersect

bool geos::geom::Envelope::intersects

(

const Coordinate &

p

)

const

Check if the point p intersects (lies inside) the region of this Envelope.

Parameters

p	the Coordinate to be tested

Returns

true if the point intersects this Envelope

bool geos::geom::Envelope::intersects	(	double	x,
		double	y
	)		const

Check if the point (x, y) intersects (lies inside) the region of this Envelope.

Parameters

x	the x-ordinate of the point
y	the y-ordinate of the point

Returns

true if the point intersects this Envelope

bool geos::geom::Envelope::intersects

(

const Envelope *

other

)

const

Check if the region defined by other Envelope intersects the region of this Envelope.

Parameters

other

the Envelope which this Envelope is being checked for intersection

Returns

true if the Envelopes intersects

bool geos::geom::Envelope::intersects

(

const Envelope &

other

)

const

bool geos::geom::Envelope::isNull

(

void

)

const

Returns true if this Envelope is a "null" envelope.

Returns

true if this Envelope is uninitialized or is the envelope of the empty geometry.

Envelope& geos::geom::Envelope::operator=

(

const Envelope &

e

)

Assignment operator.

void geos::geom::Envelope::setToNull

(

void

)

Makes this Envelope a "null" envelope, that is, the envelope of the empty geometry.

std::vector<std::string> geos::geom::Envelope::split ( const std::string &  str, const std::string &  delimiters = " "  )

private

Splits a string into parts based on the supplied delimiters.

This is a generic function that really belongs in a utility file somewhere

std::string geos::geom::Envelope::toString

(

void

)

const

Returns a string of the form Env[minx:maxx,miny:maxy].

Returns

a string of the form Env[minx:maxx,miny:maxy]

void geos::geom::Envelope::translate	(	double	transX,
		double	transY
	)

Translates this envelope by given amounts in the X and Y direction.

Parameters

transX	the amount to translate along the X axis
transY	the amount to translate along the Y axis

Friends And Related Function Documentation

std::ostream& operator<< ( std::ostream &  os, const Envelope &  o  )

friend

Output operator.

Member Data Documentation

double geos::geom::Envelope::maxx

private

the maximum x-coordinate

Definition at line 517 of file Envelope.h.

double geos::geom::Envelope::maxy

private

the maximum y-coordinate

Definition at line 523 of file Envelope.h.

double geos::geom::Envelope::minx

private

the minimum x-coordinate

Definition at line 514 of file Envelope.h.

double geos::geom::Envelope::miny

private

the minimum y-coordinate

Definition at line 520 of file Envelope.h.

---

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

• Envelope.h