#include <geos.h>
Inheritance diagram for geos::Geometry:
Public Member Functions | |
Geometry (const GeometryFactory *factory) | |
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. | |
virtual | ~Geometry () |
virtual Geometry * | clone () const =0 |
Make a deep-copy of this Geometry. | |
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 const PrecisionModel * | getPrecisionModel () const |
Get the PrecisionModel used to create this Geometry. | |
virtual const Coordinate * | getCoordinate () const =0 |
Returns a vertex of this Geometry. | |
virtual CoordinateSequence * | getCoordinates () const =0 |
Returns this Geometry vertices. Caller takes ownership of the returned object. | |
virtual int | getNumPoints () const =0 |
Returns the count of this Geometrys vertices. | |
virtual bool | isSimple () const =0 |
Returns false if the Geometry not simple. | |
virtual 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 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 int | getDimension () const =0 |
Returns the dimension of this Geometry (0=point, 1=line, 2=surface). | |
virtual Geometry * | getBoundary () const =0 |
Returns the boundary, or the empty geometry 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 |
Returns true if the DE-9IM intersection matrix for the two Geometrys is FF*FF****. | |
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 |
Returns true if the DE-9IM intersection matrix for the two Geometrys is T*T****** (for a point and a curve, a point and an area or a line and an area) 0******** (for two curves). | |
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, string intersectionPattern) const |
Returns true if the elements in the DE-9IM intersection matrix for the two Geometrys match the elements in intersectionPattern. | |
virtual IntersectionMatrix * | relate (const Geometry *g) const |
Returns the DE-9IM intersection matrix for the two Geometrys. | |
virtual bool | equals (const Geometry *g) const |
Returns true if the DE-9IM intersection matrix for the two Geometrys is T*F**FFF*. | |
virtual string | toString () const |
Returns the Well-known Text representation of this Geometry. | |
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 * | 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. | |
virtual Geometry * | Union (const Geometry *other) const |
Returns a Geometry representing all the points in this Geometry and other. | |
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) const =0 |
Returns true if the two Geometrys are exactly equal, up to a specified tolerance. | |
virtual void | normalize ()=0 |
Converts this Geometry to normal form (or canonical form). | |
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) |
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 Point * | getInteriorPoint () |
Computes an interior point of this Geometry. | |
virtual void | geometryChanged () |
void | geometryChangedAction () |
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. | |
Geometry * | toInternalGeometry (const Geometry *g) const |
Static Protected Member Functions | |
static bool | hasNonEmptyElements (const 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 vector< Geometry * > *lrs) |
Returns true if the vector contains any null elements. |
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.
The results computed by the set-theoretic methods may contain constructed points which are not present in the input Geometry
s. These new points arise from intersections between line segments in the edges of the input Geometry
s. 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.
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Destroy Geometry and all components |
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Returns a buffer region around this Geometry having the given width and with a specified number of segments used to approximate curves.
Returns a buffer region around this
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Returns the minimum distance between this Geometry and the Geometry g. Returns the minimum distance between this Geometry and the other Geometry
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Notifies this Geometry that its Coordinates have been changed by an external party (using a CoordinateFilter, for example). The Geometry will flush and/or update any information it has cached (such as its Envelope ). |
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Notifies this Geometry that its Coordinates have been changed by an external party. When geometryChanged is called, this method will be called for this Geometry and its component Geometries.
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Returns the area of this Geometry.
Returns the area of this
Reimplemented in geos::GeometryCollection, and geos::Polygon. |
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Computes the centroid of this Geometry.
Computes the centroid of this
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Gets the factory which contains the context in which this geometry was created.
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Computes an interior point of this Geometry.
Computes an interior point of this
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Returns the length of this Geometry.
Returns the length of this
Reimplemented in geos::GeometryCollection, geos::LineString, and geos::Polygon. |
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Gets the user data object for this geometry, if any.
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Tests the validity of this Subclasses provide their own definition of "valid".
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Tests whether the distance from this Geometry to another is less than or equal to a specified value.
Tests whether the distance from this
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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. |
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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.
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The GEOS algorithms assume that Geometry::getCoordinate() and getCoordinates are fast, which may not be the case if the CoordinateSequence is not a DefaultCoordinateSequence (e.g. if it were implemented using separate arrays for the x- and y-values), in which case frequent construction of Coordinates takes up much space and time. To solve this performance problem, toInternalGeometry converts the Geometry to a DefaultCoordinateSequence implementation before sending it to the JTS algorithms. |