GEOS  3.8.0dev
Public Types | Public Member Functions | Static Public Member Functions | Protected Member Functions | List of all members
geos::geom::CoordinateSequence Class Referenceabstract

The internal representation of a list of coordinates inside a Geometry. More...

#include <geos.h>

Inheritance diagram for geos::geom::CoordinateSequence:
geos::geom::CoordinateArraySequence

Public Types

enum  { X, Y, Z, M }
 Standard ordinate index values.
 
typedef std::unique_ptr
< CoordinateSequence
Ptr
 

Public Member Functions

virtual std::unique_ptr
< CoordinateSequence
clone () const =0
 Returns a deep copy of this collection.
 
virtual const CoordinategetAt (std::size_t i) const =0
 Returns a read-only reference to Coordinate at position i. More...
 
const Coordinateback () const
 Return last Coordinate in the sequence.
 
const Coordinatefront () const
 Return first Coordinate in the sequence.
 
const Coordinateoperator[] (std::size_t i) const
 
virtual void getAt (std::size_t i, Coordinate &c) const =0
 Write Coordinate at position i to given Coordinate.
 
virtual std::size_t getSize () const =0
 Returns the number of Coordinates (actual or otherwise, as this implementation may not store its data in Coordinate objects).
 
size_t size () const
 
virtual void toVector (std::vector< Coordinate > &coords) const =0
 
virtual bool isEmpty () const =0
 Returns true it list contains no coordinates.
 
virtual void setAt (const Coordinate &c, std::size_t pos)=0
 Copy Coordinate c to position pos.
 
std::string toString () const
 Get a string representation of CoordinateSequence.
 
virtual void setPoints (const std::vector< Coordinate > &v)=0
 Substitute Coordinate list with a copy of the given vector.
 
bool hasRepeatedPoints () const
 Returns true if contains any two consecutive points.
 
const CoordinateminCoordinate () const
 Returns lower-left Coordinate in list.
 
virtual std::size_t getDimension () const =0
 
virtual double getOrdinate (std::size_t index, std::size_t ordinateIndex) const =0
 
virtual double getX (std::size_t index) const
 
virtual double getY (std::size_t index) const
 
virtual void setOrdinate (std::size_t index, std::size_t ordinateIndex, double value)=0
 
virtual void expandEnvelope (Envelope &env) const
 
virtual void apply_rw (const CoordinateFilter *filter)=0
 
virtual void apply_ro (CoordinateFilter *filter) const =0
 
template<class T >
void applyCoordinateFilter (T &f)
 Apply a filter to each Coordinate of this sequence. The filter is expected to provide a .filter(Coordinate&) method. More...
 

Static Public Member Functions

static bool hasRepeatedPoints (const CoordinateSequence *cl)
 Returns true if given CoordinateSequence contains any two consecutive Coordinate.
 
static CoordinateSequenceatLeastNCoordinatesOrNothing (std::size_t n, CoordinateSequence *c)
 Returns either the given CoordinateSequence if its length is greater than the given amount, or an empty CoordinateSequence.
 
static size_t indexOf (const Coordinate *coordinate, const CoordinateSequence *cl)
 Return position of a Coordinate, or -1 if not found. More...
 
static bool equals (const CoordinateSequence *cl1, const CoordinateSequence *cl2)
 Returns true if the two arrays are identical, both null, or pointwise equal.
 
static void scroll (CoordinateSequence *cl, const Coordinate *firstCoordinate)
 Scroll given CoordinateSequence so to start with given Coordinate.
 
static int increasingDirection (const CoordinateSequence &pts)
 Determines which orientation of the Coordinate array is (overall) increasing. More...
 
static void reverse (CoordinateSequence *cl)
 Reverse Coordinate order in given CoordinateSequence.
 

Protected Member Functions

 CoordinateSequence (const CoordinateSequence &)
 

Detailed Description

The internal representation of a list of coordinates inside a Geometry.

There are some cases in which you might want Geometries to store their points using something other than the GEOS Coordinate class. For example, you may want to experiment with another implementation, such as an array of Xs and an array of Ys. or you might want to use your own coordinate class, one that supports extra attributes like M-values.

You can do this by implementing the CoordinateSequence and CoordinateSequenceFactory interfaces. You would then create a GeometryFactory parameterized by your CoordinateSequenceFactory, and use this GeometryFactory to create new Geometries. All of these new Geometries will use your CoordinateSequence implementation.

Member Function Documentation

template<class T >
void geos::geom::CoordinateSequence::applyCoordinateFilter ( T &  f)
inline

Apply a filter to each Coordinate of this sequence. The filter is expected to provide a .filter(Coordinate&) method.

TODO: accept a Functor instead, will be more flexible. actually, define iterators on Geometry

virtual void geos::geom::CoordinateSequence::expandEnvelope ( Envelope env) const
virtual

Expands the given Envelope to include the coordinates in the sequence. Allows implementing classes to optimize access to coordinate values.

Parameters
envthe envelope to expand

Reimplemented in geos::geom::CoordinateArraySequence.

virtual const Coordinate& geos::geom::CoordinateSequence::getAt ( std::size_t  i) const
pure virtual

Returns a read-only reference to Coordinate at position i.

Whether or not the Coordinate returned is the actual underlying Coordinate or merely a copy depends on the implementation.

Implemented in geos::geom::CoordinateArraySequence.

virtual std::size_t geos::geom::CoordinateSequence::getDimension ( ) const
pure virtual

Returns the dimension (number of ordinates in each coordinate) for this sequence.

Returns
the dimension of the sequence.

Implemented in geos::geom::CoordinateArraySequence.

virtual double geos::geom::CoordinateSequence::getOrdinate ( std::size_t  index,
std::size_t  ordinateIndex 
) const
pure virtual

Returns the ordinate of a coordinate in this sequence. Ordinate indices 0 and 1 are assumed to be X and Y. Ordinates indices greater than 1 have user-defined semantics (for instance, they may contain other dimensions or measure values).

Parameters
indexthe coordinate index in the sequence
ordinateIndexthe ordinate index in the coordinate (in range [0, dimension-1])
virtual double geos::geom::CoordinateSequence::getX ( std::size_t  index) const
inlinevirtual

Returns ordinate X (0) of the specified coordinate.

Parameters
index
Returns
the value of the X ordinate in the index'th coordinate
virtual double geos::geom::CoordinateSequence::getY ( std::size_t  index) const
inlinevirtual

Returns ordinate Y (1) of the specified coordinate.

Parameters
index
Returns
the value of the Y ordinate in the index'th coordinate
static int geos::geom::CoordinateSequence::increasingDirection ( const CoordinateSequence pts)
static

Determines which orientation of the Coordinate array is (overall) increasing.

In other words, determines which end of the array is "smaller" (using the standard ordering on Coordinate). Returns an integer indicating the increasing direction. If the sequence is a palindrome, it is defined to be oriented in a positive direction.

Parameters
ptsthe array of Coordinates to test
Returns
1 if the array is smaller at the start or is a palindrome, -1 if smaller at the end

NOTE: this method is found in CoordinateArrays class for JTS

static size_t geos::geom::CoordinateSequence::indexOf ( const Coordinate coordinate,
const CoordinateSequence cl 
)
static

Return position of a Coordinate, or -1 if not found.

FIXME: return std::size_t, using numeric_limits<std::size_t>::max as 'not found' value.

virtual void geos::geom::CoordinateSequence::setOrdinate ( std::size_t  index,
std::size_t  ordinateIndex,
double  value 
)
pure virtual

Sets the value for a given ordinate of a coordinate in this sequence.

Parameters
indexthe coordinate index in the sequence
ordinateIndexthe ordinate index in the coordinate (in range [0, dimension-1])
valuethe new ordinate value

Implemented in geos::geom::CoordinateArraySequence.

virtual void geos::geom::CoordinateSequence::toVector ( std::vector< Coordinate > &  coords) const
pure virtual

Pushes all Coordinates of this sequence into the provided vector.

This method is a port of the toCoordinateArray() method of JTS.

Implemented in geos::geom::CoordinateArraySequence.


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