# geos::geom::prep::PreparedGeometry Class Reference

An interface for classes which prepare Geometrys in order to optimize the performance of repeated calls to specific geometric operations. More...

`#include <PreparedGeometry.h>`

Inheritance diagram for geos::geom::prep::PreparedGeometry:

List of all members.

## Public Member Functions

virtual const geom::Geometry & | getGeometry () const =0
virtual bool | contains (const geom::Geometry *geom) const =0
virtual bool | containsProperly (const geom::Geometry *geom) const =0
| Tests whether the base Geometry properly contains a given geometry.
virtual bool | coveredBy (const geom::Geometry *geom) const =0
virtual bool | covers (const geom::Geometry *geom) const =0
virtual bool | crosses (const geom::Geometry *geom) const =0
virtual bool | disjoint (const geom::Geometry *geom) const =0
virtual bool | intersects (const geom::Geometry *geom) const =0
virtual bool | overlaps (const geom::Geometry *geom) const =0
virtual bool | touches (const geom::Geometry *geom) const =0
virtual bool | within (const geom::Geometry *geom) const =0

## Detailed Description

An interface for classes which prepare Geometrys in order to optimize the performance of repeated calls to specific geometric operations.

A given implementation may provide optimized implementations for only some of the specified methods, and delegate the remaining methods to the original Geometry operations. An implementation may also only optimize certain situations, and delegate others. See the implementing classes for documentation about which methods and situations they optimize.

## Member Function Documentation

virtual bool geos::geom::prep::PreparedGeometry::contains | ( | const geom::Geometry * | geom ) | const`[pure virtual]`

Tests whether the base Geometry contains a given geometry.

Parameters:

  geom | the Geometry to test

Returns:
  true if this Geometry contains the given Geometry

See also:
  Geometry::contains(Geometry)

Implemented in geos::geom::prep::BasicPreparedGeometry, and geos::geom::prep::PreparedPolygon.

virtual bool geos::geom::prep::PreparedGeometry::containsProperly | ( | const geom::Geometry * | geom ) | const`[pure virtual]`

Tests whether the base Geometry properly contains a given geometry.

The `containsProperly` predicate has the following equivalent definitions:

- Every point of the other geometry is a point of this geometry's interior.
- The DE-9IM Intersection Matrix for the two geometries matches `[T**FF*FF*]`

In other words, if the test geometry has any interaction with the boundary of the target geometry the result of `containsProperly` is `false`. This is different semantics to the Geometry::contains predicate, * in which test geometries can intersect the target's boundary and still be contained.

The advantage of using this predicate is that it can be computed efficiently, since it avoids the need to compute the full topological relationship of the input boundaries in cases where they intersect.

An example use case is computing the intersections of a set of geometries with a large polygonal geometry. Since `intersection` is a fairly slow operation, it can be more efficient to use `containsProperly` to filter out test geometries which lie wholly inside the area. In these cases the intersection is known a priori to be exactly the original test geometry.

Parameters:

  geom | the Geometry to test

Returns:
  true if this Geometry properly contains the given Geometry

See also:
  Geometry::contains

Implemented in geos::geom::prep::BasicPreparedGeometry, and geos::geom::prep::PreparedPolygon.

virtual bool geos::geom::prep::PreparedGeometry::coveredBy | ( | const geom::Geometry * | geom ) | const`[pure virtual]`

Tests whether the base Geometry is covered by a given geometry.

Parameters:

  geom | the Geometry to test

Returns:
  true if this Geometry is covered by the given Geometry

See also:
  Geometry::coveredBy(Geometry)

Implemented in geos::geom::prep::BasicPreparedGeometry.

virtual bool geos::geom::prep::PreparedGeometry::covers | ( | const geom::Geometry * | geom ) | const`[pure virtual]`

Tests whether the base Geometry covers a given geometry.

Parameters:

  geom | the Geometry to test

Returns:
  true if this Geometry covers the given Geometry

See also:
  Geometry::covers(Geometry)

Implemented in geos::geom::prep::BasicPreparedGeometry, and geos::geom::prep::PreparedPolygon.

virtual bool geos::geom::prep::PreparedGeometry::crosses | ( | const geom::Geometry * | geom ) | const`[pure virtual]`

Tests whether the base Geometry crosses a given geometry.

Parameters:

  geom | the Geometry to test

Returns:
  true if this Geometry crosses the given Geometry

See also:
  Geometry::crosses(Geometry)

Implemented in geos::geom::prep::BasicPreparedGeometry.

virtual bool geos::geom::prep::PreparedGeometry::disjoint | ( | const geom::Geometry * | geom ) | const`[pure virtual]`

Tests whether the base Geometry is disjoint from a given geometry.

Parameters:

  geom | the Geometry to test

Returns:
  true if this Geometry is disjoint from the given Geometry

See also:
  Geometry::disjoint(Geometry)

Implemented in geos::geom::prep::BasicPreparedGeometry.

virtual const geom::Geometry& geos::geom::prep::PreparedGeometry::getGeometry | ( | ) | const`[pure virtual]`

Gets the original Geometry which has been prepared.

Returns:
  the base geometry

Implemented in geos::geom::prep::BasicPreparedGeometry.

virtual bool geos::geom::prep::PreparedGeometry::intersects | ( | const geom::Geometry * | geom ) | const`[pure virtual]`

Tests whether the base Geometry intersects a given geometry.

Parameters:

  geom | the Geometry to test

Returns:
  true if this Geometry intersects the given Geometry

See also:
  Geometry::intersects(Geometry)

Implemented in geos::geom::prep::BasicPreparedGeometry, geos::geom::prep::PreparedLineString, and geos::geom::prep::PreparedPolygon.

virtual bool geos::geom::prep::PreparedGeometry::overlaps | ( | const geom::Geometry * | geom ) | const`[pure virtual]`

Tests whether the base Geometry overlaps a given geometry.

Parameters:

  geom | the Geometry to test

Returns:
  true if this Geometry overlaps the given Geometry

See also:
  Geometry::overlaps(Geometry)

Implemented in geos::geom::prep::BasicPreparedGeometry.

virtual bool geos::geom::prep::PreparedGeometry::touches | ( | const geom::Geometry * | geom ) | const`[pure virtual]`

Tests whether the base Geometry touches a given geometry.

Parameters:

  geom | the Geometry to test

Returns:
  true if this Geometry touches the given Geometry

See also:
  Geometry::touches(Geometry)

Implemented in geos::geom::prep::BasicPreparedGeometry.

virtual bool geos::geom::prep::PreparedGeometry::within | ( | const geom::Geometry * | geom ) | const`[pure virtual]`

Tests whether the base Geometry is within a given geometry.

Parameters:

  geom | the Geometry to test

Returns:
  true if this Geometry is within the given Geometry

See also:
  Geometry::within(Geometry)

Implemented in geos::geom::prep::BasicPreparedGeometry.

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

- PreparedGeometry.h