Class GeometrySnapper

Hierarchy: Object , GeometrySnapper

public class GeometrySnapper

Snaps the vertices and segments of a Geometry to another Geometry's vertices. A snap distance tolerance is used to control where snapping is performed. Snapping one geometry to another can improve robustness for overlay operations by eliminating nearly-coincident edges (which cause problems during noding and intersection calculation). It can also be used to eliminate artifacts such as narrow slivers, spikes and gores.

Too much snapping can result in invalid topology being created, so the number and location of snapped vertices is decided using heuristics to determine when it is safe to snap. This can result in some potential snaps being omitted, however.

Authors:: Martin Davis

Other

version: 1.7

public GeometrySnapper(Geometry srcGeom)

Creates a new snapper acting on the given geometry

Parameters:: srcGeom - srcGeom the geometry to snap

public static double computeOverlaySnapTolerance(Geometry g)

Estimates the snap tolerance for a Geometry, taking into account its precision model.

Parameters:: g - g a Geometry

Returns:: the estimated snap tolerance

public static double computeSizeBasedSnapTolerance(Geometry g)

public static double computeOverlaySnapTolerance(Geometry g0, Geometry g1)

public static Geometry[] snap(Geometry g0, Geometry g1, double snapTolerance)

Snaps two geometries together with a given tolerance.

Parameters:: g0 - g0 a geometry to snap; g1 - g1 a geometry to snap; snapTolerance - snapTolerance the tolerance to use

Returns:: the snapped geometries

public static Geometry snapToSelf(Geometry geom, double snapTolerance, boolean cleanResult)

Snaps a geometry to itself. Allows optionally cleaning the result to ensure it is topologically valid (which fixes issues such as topology collapses in polygonal inputs).

Snapping a geometry to itself can remove artifacts such as very narrow slivers, gores and spikes.

Parameters:: geom - geom the geometry to snap; snapTolerance - snapTolerance the snapping tolerance; cleanResult - cleanResult whether the result should be made valid

Returns:: a new snapped Geometry

public Geometry snapTo(Geometry snapGeom, double snapTolerance)

Snaps the vertices in the component LineStrings of the source geometry to the vertices of the given snap geometry.

Parameters:: snapGeom - snapGeom a geometry to snap the source to

Returns:: a new snapped Geometry

public Geometry snapToSelf(double snapTolerance, boolean cleanResult)

Snaps the vertices in the component LineStrings of the source geometry to the vertices of the same geometry. Allows optionally cleaning the result to ensure it is topologically valid (which fixes issues such as topology collapses in polygonal inputs).

Parameters:: snapTolerance - snapTolerance the snapping tolerance; cleanResult - cleanResult whether the result should be made valid

Returns:: a new snapped Geometry