GEOS  3.8.0dev
Public Member Functions | List of all members
geos::operation::valid::ConsistentAreaTester Class Reference

Checks that a geomgraph::GeometryGraph representing an area (a geom::Polygon or geom::MultiPolygon) has consistent semantics for area geometries. This check is required for any reasonable polygonal model (including the OGC-SFS model, as well as models which allow ring self-intersection at single points) More...

#include <ConsistentAreaTester.h>

Public Member Functions

 ConsistentAreaTester (geomgraph::GeometryGraph *newGeomGraph)
 
geom::CoordinategetInvalidPoint ()
 
bool isNodeConsistentArea ()
 Check all nodes to see if their labels are consistent with area topology. More...
 
bool hasDuplicateRings ()
 

Detailed Description

Checks that a geomgraph::GeometryGraph representing an area (a geom::Polygon or geom::MultiPolygon) has consistent semantics for area geometries. This check is required for any reasonable polygonal model (including the OGC-SFS model, as well as models which allow ring self-intersection at single points)

Checks include:

If an inconsistency is found the location of the problem is recorded and is available to the caller.

Constructor & Destructor Documentation

geos::operation::valid::ConsistentAreaTester::ConsistentAreaTester ( geomgraph::GeometryGraph newGeomGraph)

Creates a new tester for consistent areas.

Parameters
newGeomGraphthe topology graph of the area geometry. Caller keeps responsibility for its deletion

Member Function Documentation

geom::Coordinate& geos::operation::valid::ConsistentAreaTester::getInvalidPoint ( )
Returns
the intersection point, or null if none was found
bool geos::operation::valid::ConsistentAreaTester::hasDuplicateRings ( )

Checks for two duplicate rings in an area. Duplicate rings are rings that are topologically equal (that is, which have the same sequence of points up to point order). If the area is topologically consistent (determined by calling the isNodeConsistentArea, duplicate rings can be found by checking for EdgeBundles which contain more than one geomgraph::EdgeEnd. (This is because topologically consistent areas cannot have two rings sharing the same line segment, unless the rings are equal). The start point of one of the equal rings will be placed in invalidPoint.

Returns
true if this area Geometry is topologically consistent but has two duplicate rings
bool geos::operation::valid::ConsistentAreaTester::isNodeConsistentArea ( )

Check all nodes to see if their labels are consistent with area topology.

Returns
true if this area has a consistent node labelling

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