GEOS  3.8.0dev
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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< EnvelopePtr
 

Public Member Functions

 Envelope (void)
 Creates a null Envelope.
 
 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.
 
Envelopeoperator= (const Envelope &e)
 Assignment operator.
 
 Envelope (const std::string &str)
 Create an Envelope from an Envelope string representation produced by Envelope::toString()
 
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.
 
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.
 
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.
 
double getMaxX () const
 Returns the Envelope maximum x-value. min x > max x indicates that this is a null Envelope.
 
double getMinY () const
 Returns the Envelope minimum y-value. min y > max y indicates that this is a null Envelope.
 
double getMinX () const
 Returns the Envelope minimum x-value. min x > max x indicates that this is a null Envelope.
 
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...
 
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 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...
 
int 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...
 

Friends

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

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.

Constructor & Destructor Documentation

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
x1the first x-value
x2the second x-value
y1the first y-value
y2the second y-value
geos::geom::Envelope::Envelope ( const Coordinate p1,
const Coordinate p2 
)

Creates an Envelope for a region defined by two Coordinates.

Parameters
p1the first Coordinate
p2the second Coordinate
geos::geom::Envelope::Envelope ( const Coordinate p)

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

Parameters
pthe Coordinate

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
centreThe 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
otherthe Envelope to check
Returns
true if other is contained in this Envelope
See also
covers(Envelope)
bool geos::geom::Envelope::contains ( const Coordinate p) const
inline

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

Parameters
pthe 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.

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
xthe x-coordinate of the point which this Envelope is being checked for containing
ythe 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 ( double  x,
double  y 
) const

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

Parameters
xthe x-coordinate of the point which this Envelope is being checked for containing
ythe 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
pthe 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
otherthe Envelope to check
Returns
true if this Envelope covers the other
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.

bool geos::geom::Envelope::equals ( const Envelope other) const

Returns true if the Envelope other spatially equals this Envelope.

Parameters
otherthe 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
deltaXthe distance to expand the envelope along the X axis
deltaYthe 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_distancethe distance to expand the envelope
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
pthe 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
xthe value to lower the minimum x to or to raise the maximum x to
ythe 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
otherthe Envelope to merge with
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
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::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
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
x1the first x-value
x2the second x-value
y1the first y-value
y2the 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
p1the first Coordinate
p2the second Coordinate
void geos::geom::Envelope::init ( const Coordinate p)

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

Parameters
pthe Coordinate
bool geos::geom::Envelope::intersection ( const Envelope env,
Envelope result 
) const

Computes the intersection of two Envelopes.

Parameters
envthe envelope to intersect with
resultthe 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
p1one extremal point of the envelope
p2another extremal point of the envelope
qthe 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
p1one extremal point of the envelope P
p2another extremal point of the envelope P
q1one extremal point of the envelope Q
q2another 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
aa point
banother 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
pthe 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
xthe x-ordinate of the point
ythe 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
otherthe Envelope which this Envelope is being checked for intersection
Returns
true if the Envelopes intersects
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.
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
transXthe amount to translate along the X axis
transYthe amount to translate along the Y axis

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