Basic implementation of Geometry, constructed and destructed by GeometryFactory. More...
#include <geos.h>
Public Types | |
typedef std::vector< const Geometry * > | ConstVect |
A vector of const Geometry pointers. | |
typedef std::vector< Geometry * > | NonConstVect |
A vector of non-const Geometry pointers. | |
typedef std::auto_ptr< Geometry > | AutoPtr |
An auto_ptr of Geometry. | |
Public Member Functions | |
virtual Geometry * | clone () const =0 |
Make a deep-copy of this Geometry. | |
virtual | ~Geometry () |
Destroy Geometry and all components. | |
const GeometryFactory * | getFactory () const |
Gets the factory which contains the context in which this geometry was created. | |
void | setUserData (void *newUserData) |
A simple scheme for applications to add their own custom data to a Geometry. An example use might be to add an object representing a Coordinate Reference System. | |
void * | getUserData () |
Gets the user data object for this geometry, if any. | |
virtual int | getSRID () const |
virtual void | setSRID (int newSRID) |
const PrecisionModel * | getPrecisionModel () const |
Get the PrecisionModel used to create this Geometry. | |
virtual const Coordinate * | getCoordinate () const =0 |
Returns a vertex of this Geometry, or NULL if this is the empty geometry. | |
virtual CoordinateSequence * | getCoordinates () const =0 |
Returns this Geometry vertices. Caller takes ownership of the returned object. | |
virtual std::size_t | getNumPoints () const =0 |
Returns the count of this Geometrys vertices. | |
virtual bool | isSimple () const |
Returns false if the Geometry not simple. | |
virtual std::string | getGeometryType () const =0 |
Return a string representation of this Geometry type. | |
virtual GeometryTypeId | getGeometryTypeId () const =0 |
Return an integer representation of this Geometry type. | |
virtual std::size_t | getNumGeometries () const |
virtual const Geometry * | getGeometryN (std::size_t) const |
virtual bool | isValid () const |
Tests the validity of this Geometry . | |
virtual bool | isEmpty () const =0 |
Returns whether or not the set of points in this Geometry is empty. | |
virtual bool | isRectangle () const |
Polygon overrides to check for actual rectangle. | |
virtual Dimension::DimensionType | getDimension () const =0 |
Returns the dimension of this Geometry (0=point, 1=line, 2=surface). | |
virtual int | getCoordinateDimension () const =0 |
Returns the coordinate dimension of this Geometry (2=XY, 3=XYZ, 4=XYZM in future). | |
virtual Geometry * | getBoundary () const =0 |
Returns the boundary, or an empty geometry of appropriate dimension if this Geometry is empty. | |
virtual int | getBoundaryDimension () const =0 |
Returns the dimension of this Geometrys inherent boundary. | |
virtual Geometry * | getEnvelope () const |
Returns this Geometrys bounding box. | |
virtual const Envelope * | getEnvelopeInternal () const |
Returns the minimum and maximum x and y values in this Geometry, or a null Envelope if this Geometry is empty. | |
virtual bool | disjoint (const Geometry *other) const |
virtual bool | touches (const Geometry *other) const |
Returns true if the DE-9IM intersection matrix for the two Geometrys is FT*******, F**T***** or F***T****. | |
virtual bool | intersects (const Geometry *g) const |
Returns true if disjoint returns false. | |
virtual bool | crosses (const Geometry *g) const |
virtual bool | within (const Geometry *g) const |
Returns true if the DE-9IM intersection matrix for the two Geometrys is T*F**F***. | |
virtual bool | contains (const Geometry *g) const |
Returns true if other.within(this) returns true. | |
virtual bool | overlaps (const Geometry *g) const |
Returns true if the DE-9IM intersection matrix for the two Geometrys is T*T***T** (for two points or two surfaces) 1*T***T** (for two curves). | |
virtual bool | relate (const Geometry *g, const std::string &intersectionPattern) const |
Returns true if the elements in the DE-9IM intersection matrix for the two Geometrys match the elements in intersectionPattern. | |
bool | relate (const Geometry &g, const std::string &intersectionPattern) const |
virtual IntersectionMatrix * | relate (const Geometry *g) const |
Returns the DE-9IM intersection matrix for the two Geometrys. | |
IntersectionMatrix * | relate (const Geometry &g) const |
virtual bool | equals (const Geometry *g) const |
Returns true if the DE-9IM intersection matrix for the two Geometrys is T*F**FFF*. | |
bool | covers (const Geometry *g) const |
Returns true if this geometry covers the specified geometry. | |
bool | coveredBy (const Geometry *g) const |
Tests whether this geometry is covered by the specified geometry. | |
virtual std::string | toString () const |
Returns the Well-known Text representation of this Geometry. | |
virtual std::string | toText () const |
virtual Geometry * | buffer (double distance) const |
Returns a buffer region around this Geometry having the given width. | |
virtual Geometry * | buffer (double distance, int quadrantSegments) const |
Returns a buffer region around this Geometry having the given width and with a specified number of segments used to approximate curves. | |
virtual Geometry * | buffer (double distance, int quadrantSegments, int endCapStyle) const |
Computes a buffer area around this geometry having the given width and with a specified accuracy of approximation for circular arcs, and using a specified end cap style. | |
virtual Geometry * | convexHull () const |
Returns the smallest convex Polygon that contains all the points in the Geometry. | |
virtual Geometry * | intersection (const Geometry *other) const |
Returns a Geometry representing the points shared by this Geometry and other. | |
Geometry * | Union (const Geometry *other) const |
Returns a Geometry representing all the points in this Geometry and other. | |
AutoPtr | Union () const |
virtual Geometry * | difference (const Geometry *other) const |
Returns a Geometry representing the points making up this Geometry that do not make up other. | |
virtual Geometry * | symDifference (const Geometry *other) const |
Returns a set combining the points in this Geometry not in other, and the points in other not in this Geometry. | |
virtual bool | equalsExact (const Geometry *other, double tolerance=0) const =0 |
Returns true if the two Geometrys are exactly equal, up to a specified tolerance. | |
virtual void | apply_rw (const CoordinateFilter *filter)=0 |
virtual void | apply_ro (CoordinateFilter *filter) const =0 |
virtual void | apply_rw (GeometryFilter *filter) |
virtual void | apply_ro (GeometryFilter *filter) const |
virtual void | apply_rw (GeometryComponentFilter *filter) |
virtual void | apply_ro (GeometryComponentFilter *filter) const |
virtual void | apply_rw (CoordinateSequenceFilter &filter)=0 |
virtual void | apply_ro (CoordinateSequenceFilter &filter) const =0 |
template<class T > | |
void | applyComponentFilter (T &f) const |
Apply a fiter to each component of this geometry. The filter is expected to provide a .filter(const Geometry*) method. | |
virtual void | normalize ()=0 |
Converts this Geometry to normal form (or canonical form). | |
virtual int | compareTo (const Geometry *geom) const |
virtual double | distance (const Geometry *g) const |
Returns the minimum distance between this Geometry and the Geometry g. | |
virtual double | getArea () const |
Returns the area of this Geometry. | |
virtual double | getLength () const |
Returns the length of this Geometry. | |
virtual bool | isWithinDistance (const Geometry *geom, double cDistance) const |
Tests whether the distance from this Geometry to another is less than or equal to a specified value. | |
virtual Point * | getCentroid () const |
Computes the centroid of this Geometry . | |
virtual bool | getCentroid (Coordinate &ret) const |
Computes the centroid of this Geometry as a Coordinate. | |
virtual Point * | getInteriorPoint () const |
Computes an interior point of this Geometry . | |
virtual void | geometryChanged () |
void | geometryChangedAction () |
Notifies this Geometry that its Coordinates have been changed by an external party. | |
Protected Member Functions | |
virtual bool | isEquivalentClass (const Geometry *other) const |
Returns whether the two Geometrys are equal, from the point of view of the equalsExact method. | |
virtual Envelope::AutoPtr | computeEnvelopeInternal () const =0 |
virtual int | compareToSameClass (const Geometry *geom) const =0 |
int | compare (std::vector< Coordinate > a, std::vector< Coordinate > b) const |
int | compare (std::vector< Geometry * > a, std::vector< Geometry * > b) const |
bool | equal (const Coordinate &a, const Coordinate &b, double tolerance) const |
Geometry (const Geometry &geom) | |
Polygon overrides to check for actual rectangle. | |
Geometry (const GeometryFactory *factory) | |
Construct a geometry with the given GeometryFactory. | |
Static Protected Member Functions | |
static bool | hasNonEmptyElements (const std::vector< Geometry * > *geometries) |
Returns true if the array contains any non-empty Geometrys. | |
static bool | hasNullElements (const CoordinateSequence *list) |
Returns true if the CoordinateSequence contains any null elements. | |
static bool | hasNullElements (const std::vector< Geometry * > *lrs) |
Returns true if the vector contains any null elements. | |
static void | checkNotGeometryCollection (const Geometry *g) |
Protected Attributes | |
std::auto_ptr< Envelope > | envelope |
The bounding box of this Geometry. | |
int | SRID |
Friends | |
class | GeometryFactory |
Basic implementation of Geometry, constructed and destructed by GeometryFactory.
clone
returns a deep copy of the object. Use GeometryFactory to construct.
Because it is not clear at this time what semantics for spatial analysis methods involving GeometryCollection
s would be useful, GeometryCollection
s are not supported as arguments to binary predicates (other than convexHull
) or the relate
method.
The spatial analysis methods will return the most specific class possible to represent the result. If the result is homogeneous, a Point
, LineString
, or Polygon
will be returned if the result contains a single element; otherwise, a MultiPoint
, MultiLineString
, or MultiPolygon
will be returned. If the result is heterogeneous a GeometryCollection
will be returned.
Because it is not clear at this time what semantics for set-theoretic methods involving GeometryCollection
s would be useful, GeometryCollections
are not supported as arguments to the set-theoretic methods.
The SFS states that the result of a set-theoretic method is the "point-set" result of the usual set-theoretic definition of the operation (SFS 3.2.21.1). However, there are sometimes many ways of representing a point set as a Geometry
.
The SFS does not specify an unambiguous representation of a given point set returned from a spatial analysis method. One goal of JTS is to make this specification precise and unambiguous. JTS will use a canonical form for Geometry
s returned from spatial analysis methods. The canonical form is a Geometry
which is simple and noded:
isSimple
. LineString
s. It means that all intersection points on LineString
s will be present as endpoints of LineString
s in the result. This definition implies that non-simple geometries which are arguments to spatial analysis methods must be subjected to a line-dissolve process to ensure that the results are simple.
The results computed by the set-theoretic methods may contain constructed points which are not present in the input Geometry. These new points arise from intersections between line segments in the edges of the input Geometry. In the general case it is not possible to represent constructed points exactly. This is due to the fact that the coordinates of an intersection point may contain twice as many bits of precision as the coordinates of the input line segments. In order to represent these constructed points explicitly, JTS must truncate them to fit the PrecisionModel.
Unfortunately, truncating coordinates moves them slightly. Line segments which would not be coincident in the exact result may become coincident in the truncated representation. This in turn leads to "topology collapses" -- situations where a computed element has a lower dimension than it would in the exact result.
When JTS detects topology collapses during the computation of spatial analysis methods, it will throw an exception. If possible the exception will report the location of the collapse.
equals(Object) and hashCode are not overridden, so that when two topologically equal Geometries are added to HashMaps and HashSets, they remain distinct. This behaviour is desired in many cases.
geos::geom::Geometry::Geometry | ( | const Geometry & | geom | ) | [protected] |
geos::geom::Geometry::Geometry | ( | const GeometryFactory * | factory | ) | [protected] |
Construct a geometry with the given GeometryFactory.
Will keep a reference to the factory, so don't delete it until al Geometry objects referring to it are deleted.
factory |
virtual void geos::geom::Geometry::apply_ro | ( | CoordinateSequenceFilter & | filter | ) | const [pure virtual] |
Performs a read-only operation on the coordinates in this Geometry's CoordinateSequences.
filter | the filter to apply |
Implemented in geos::geom::GeometryCollection, geos::geom::LineString, geos::geom::Point, and geos::geom::Polygon.
virtual void geos::geom::Geometry::apply_rw | ( | CoordinateSequenceFilter & | filter | ) | [pure virtual] |
Performs an operation on the coordinates in this Geometry's CoordinateSequences.s If the filter reports that a coordinate value has been changed, geometryChanged will be called automatically.
filter | the filter to apply |
Implemented in geos::geom::GeometryCollection, geos::geom::LineString, geos::geom::Point, and geos::geom::Polygon.
void geos::geom::Geometry::applyComponentFilter | ( | T & | f | ) | const [inline] |
Apply a fiter to each component of this geometry. The filter is expected to provide a .filter(const Geometry*) method.
I intend similar templated methods to replace all the virtual apply_rw and apply_ro functions... --strk(2005-02-06);
Referenced by geos::operation::linemerge::LineSequencer::add().
virtual Geometry* geos::geom::Geometry::buffer | ( | double | distance, | |
int | quadrantSegments | |||
) | const [virtual] |
Returns a buffer region around this Geometry having the given width and with a specified number of segments used to approximate curves.
util::TopologyException | if a robustness error occurs |
virtual Geometry* geos::geom::Geometry::buffer | ( | double | distance, | |
int | quadrantSegments, | |||
int | endCapStyle | |||
) | const [virtual] |
Computes a buffer area around this geometry having the given width and with a specified accuracy of approximation for circular arcs, and using a specified end cap style.
Buffer area boundaries can contain circular arcs. To represent these arcs using linear geometry they must be approximated with line segments.
The quadrantSegments
argument allows controlling the accuracy of the approximation by specifying the number of line segments used to represent a quadrant of a circle
The end cap style specifies the buffer geometry that will be created at the ends of linestrings. The styles provided are:
distance | the width of the buffer (may be positive, negative or 0) | |
quadrantSegments | the number of line segments used to represent a quadrant of a circle | |
endCapStyle | the end cap style to use |
util::TopologyException | if a robustness error occurs |
virtual Geometry* geos::geom::Geometry::buffer | ( | double | distance | ) | const [virtual] |
Returns a buffer region around this Geometry having the given width.
util::TopologyException | if a robustness error occurs |
bool geos::geom::Geometry::coveredBy | ( | const Geometry * | g | ) | const [inline] |
Tests whether this geometry is covered by the specified geometry.
The coveredBy
predicate has the following equivalent definitions:
[T*F**F***]
or [*TF**F***]
or [**FT*F***]
or [**F*TF***]
g.covers(this)
(coveredBy
is the converse of covers
)If either geometry is empty, the value of this predicate is false
.
This predicate is similar to within, but is more inclusive (i.e. returns true
for more cases).
true
if this Geometry
is covered by g
References covers().
bool geos::geom::Geometry::covers | ( | const Geometry * | g | ) | const |
Returns true
if this geometry covers the specified geometry.
The covers
predicate has the following equivalent definitions:
T*****FF*
or *T****FF*
or ***T**FF*
or ****T*FF*
g.coveredBy(this)
(covers
is the inverse of coveredBy
)If either geometry is empty, the value of this predicate is false
.
This predicate is similar to contains, but is more inclusive (i.e. returns true
for more cases). In particular, unlike contains
it does not distinguish between points in the boundary and in the interior of geometries. For most situations, covers
should be used in preference to contains
. As an added benefit, covers
is more amenable to optimization, and hence should be more performant.
true
if this Geometry
covers g
Referenced by coveredBy().
virtual bool geos::geom::Geometry::crosses | ( | const Geometry * | g | ) | const [virtual] |
Tests whether this geometry crosses the specified geometry.
The crosses
predicate has the following equivalent definitions:
[T*T******]
(for P/L, P/A, and L/A situations)[T*****T**]
(for L/P, A/P, and A/L situations)[0********]
(for L/L situations) For any other combination of dimensions this predicate returns false
.The SFS defined this predicate only for P/L, P/A, L/L, and L/A situations. JTS extends the definition to apply to L/P, A/P and A/L situations as well, in order to make the relation symmetric.
true
if the two Geometry
s cross. Returns a Geometry representing the points making up this Geometry that do not make up other.
util::TopologyException | if a robustness error occurs | |
util::IllegalArgumentException | if either input is a non-empty GeometryCollection |
virtual bool geos::geom::Geometry::disjoint | ( | const Geometry * | other | ) | const [virtual] |
Tests whether this geometry is disjoint from the specified geometry.
The disjoint
predicate has the following equivalent definitions:
[FF*FF****]
! g.intersects(this)
(disjoint
is the inverse of intersects
)Geometry
s are disjointvirtual Geometry* geos::geom::Geometry::getBoundary | ( | ) | const [pure virtual] |
Returns the boundary, or an empty geometry of appropriate dimension if this Geometry
is empty.
(In the case of zero-dimensional geometries, an empty GeometryCollection is returned.) For a discussion of this function, see the OpenGIS Simple Features Specification. As stated in SFS Section 2.1.13.1, "the boundary of a Geometry is a set of Geometries of the next lower dimension."
Geometry
. Ownershipof the returned object transferred to caller. Implemented in geos::geom::GeometryCollection, geos::geom::LineString, geos::geom::MultiLineString, geos::geom::MultiPoint, geos::geom::MultiPolygon, geos::geom::Point, and geos::geom::Polygon.
virtual bool geos::geom::Geometry::getCentroid | ( | Coordinate & | ret | ) | const [virtual] |
Computes the centroid of this Geometry as a Coordinate.
Returns false if centroid cannot be computed (EMPTY geometry)
virtual Point* geos::geom::Geometry::getCentroid | ( | ) | const [virtual] |
const GeometryFactory* geos::geom::Geometry::getFactory | ( | ) | const [inline] |
Gets the factory which contains the context in which this geometry was created.
virtual const Geometry* geos::geom::Geometry::getGeometryN | ( | std::size_t | ) | const [inline, virtual] |
Returns a pointer to the nth Geometry int this collection (or self if this is not a collection)
Reimplemented in geos::geom::GeometryCollection.
virtual Point* geos::geom::Geometry::getInteriorPoint | ( | ) | const [virtual] |
virtual std::size_t geos::geom::Geometry::getNumGeometries | ( | ) | const [inline, virtual] |
Returns the number of geometries in this collection (or 1 if this is not a collection)
Reimplemented in geos::geom::GeometryCollection.
void* geos::geom::Geometry::getUserData | ( | ) | [inline] |
Gets the user data object for this geometry, if any.
null
if none set Returns a Geometry representing the points shared by this Geometry and other.
util::TopologyException | if a robustness error occurs | |
util::IllegalArgumentException | if either input is a non-empty GeometryCollection |
virtual bool geos::geom::Geometry::isValid | ( | ) | const [virtual] |
virtual bool geos::geom::Geometry::isWithinDistance | ( | const Geometry * | geom, | |
double | cDistance | |||
) | const [virtual] |
Tests whether the distance from this Geometry to another is less than or equal to a specified value.
geom | the Geometry to check the distance to | |
cDistance | the distance value to compare |
true
if the geometries are less than distance
apart.virtual bool geos::geom::Geometry::relate | ( | const Geometry * | g, | |
const std::string & | intersectionPattern | |||
) | const [virtual] |
Returns true if the elements in the DE-9IM intersection matrix for the two Geometrys match the elements in intersectionPattern.
IntersectionPattern elements may be: 0 1 2 T ( = 0, 1 or 2) F ( = -1) * ( = -1, 0, 1 or 2).
For more information on the DE-9IM, see the OpenGIS Simple Features Specification.
util::IllegalArgumentException | if either arg is a collection |
void geos::geom::Geometry::setUserData | ( | void * | newUserData | ) | [inline] |
A simple scheme for applications to add their own custom data to a Geometry. An example use might be to add an object representing a Coordinate Reference System.
Note that user data objects are not present in geometries created by construction methods.
newUserData | an object, the semantics for which are defined by the application using this Geometry |
Returns a set combining the points in this Geometry not in other, and the points in other not in this Geometry.
util::TopologyException | if a robustness error occurs | |
util::IllegalArgumentException | if either input is a non-empty GeometryCollection |
Returns a Geometry representing all the points in this Geometry and other.
util::TopologyException | if a robustness error occurs | |
util::IllegalArgumentException | if either input is a non-empty GeometryCollection |
AutoPtr geos::geom::Geometry::Union | ( | ) | const |
Computes the union of all the elements of this geometry. Heterogeneous GeometryCollections are fully supported.
The result obeys the following contract: