GEOS  3.8.0dev
Classes
geos::operation::overlay Namespace Reference

Contains classes that perform a topological overlay to compute boolean spatial functions. More...

Classes

class  EdgeSetNoder
 Nodes a set of edges. More...
 
class  LineBuilder
 Forms JTS LineStrings out of a the graph of geomgraph::DirectedEdge created by an OverlayOp. More...
 
class  MaximalEdgeRing
 A ring of edges which may contain nodes of degree > 2. More...
 
class  MinimalEdgeRing
 A ring of Edges with the property that no node has degree greater than 2. More...
 
class  OverlayNodeFactory
 Creates nodes for use in the geomgraph::PlanarGraph constructed during overlay operations. NOTE: also used by operation::valid. More...
 
struct  overlayOp
 OverlayOp::overlayOp Adapter for use with geom::BinaryOp. More...
 
class  OverlayOp
 Computes the geometric overlay of two Geometry. More...
 
class  PointBuilder
 Constructs geom::Point s from the nodes of an overlay graph. More...
 
class  PolygonBuilder
 Forms Polygon out of a graph of geomgraph::DirectedEdge. More...
 

Detailed Description

Contains classes that perform a topological overlay to compute boolean spatial functions.

The Overlay Algorithm is used in spatial analysis methods for computing set-theoretic operations (boolean combinations) of input Geometrys. The algorithm for computing the overlay uses the intersection operations supported by topology graphs. To compute an overlay it is necessary to explicitly compute the resultant graph formed by the computed intersections.

The algorithm to compute a set-theoretic spatial analysis method has the following steps:

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