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java.lang.Object com.vividsolutions.jts.triangulate.quadedge.QuadEdgeSubdivision
public class QuadEdgeSubdivision
A class that contains the QuadEdge
s representing a planar
subdivision that models a triangulation.
The subdivision is constructed using the
quadedge algebra defined in the classs QuadEdge
.
All metric calculations
are done in the Vertex
class.
In addition to a triangulation, subdivisions
support extraction of Voronoi diagrams.
This is easily accomplished, since the Voronoi diagram is the dual
of the Delaunay triangulation.
Subdivisions can be provided with a tolerance value. Inserted vertices which are closer than this value to vertices already in the subdivision will be ignored. Using a suitable tolerance value can prevent robustness failures from happening during Delaunay triangulation.
Subdivisions maintain a frame triangle around the client-created edges. The frame is used to provide a bounded "container" for all edges within a TIN. Normally the frame edges, frame connecting edges, and frame triangles are not included in client processing.
Constructor Summary | |
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QuadEdgeSubdivision(Envelope env,
double tolerance)
Creates a new instance of a quad-edge subdivision based on a frame triangle that encloses a supplied bounding box. |
Method Summary | |
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QuadEdge |
connect(QuadEdge a,
QuadEdge b)
Creates a new QuadEdge connecting the destination of a to the origin of b, in such a way that all three have the same left face after the connection is complete. |
void |
delete(QuadEdge e)
Deletes a quadedge from the subdivision. |
java.util.Collection |
getEdges()
Gets the collection of base QuadEdge s (one for every pair of
vertices which is connected). |
Geometry |
getEdges(GeometryFactory geomFact)
Gets the geometry for the edges in the subdivision as a MultiLineString
containing 2-point lines. |
Envelope |
getEnvelope()
Gets the envelope of the Subdivision (including the frame). |
java.util.List |
getPrimaryEdges(boolean includeFrame)
Gets all primary quadedges in the subdivision. |
double |
getTolerance()
Gets the vertex-equality tolerance value used in this subdivision |
java.util.List |
getTriangleCoordinates(boolean includeFrame)
Gets the coordinates for each triangle in the subdivision as an array. |
java.util.List |
getTriangleEdges(boolean includeFrame)
Gets a list of the triangles in the subdivision, specified as an array of the primary quadedges around the triangle. |
static void |
getTriangleEdges(QuadEdge startQE,
QuadEdge[] triEdge)
Gets the edges for the triangle to the left of the given QuadEdge . |
Geometry |
getTriangles(GeometryFactory geomFact)
Gets the geometry for the triangles in a triangulated subdivision as a GeometryCollection
of triangular Polygon s. |
java.util.List |
getTriangleVertices(boolean includeFrame)
Gets a list of the triangles in the subdivision, specified as an array of the triangle Vertex es. |
java.util.List |
getVertexUniqueEdges(boolean includeFrame)
Gets a collection of QuadEdge s whose origin
vertices are a unique set which includes
all vertices in the subdivision. |
java.util.Collection |
getVertices(boolean includeFrame)
Gets the unique Vertex es in the subdivision,
including the frame vertices if desired. |
Polygon |
getVoronoiCellPolygon(QuadEdge qe,
GeometryFactory geomFact)
Gets the Voronoi cell around a site specified by the origin of a QuadEdge. |
java.util.List |
getVoronoiCellPolygons(GeometryFactory geomFact)
Gets a List of Polygon s for the Voronoi cells
of this triangulation. |
Geometry |
getVoronoiDiagram(GeometryFactory geomFact)
Gets the cells in the Voronoi diagram for this triangulation. |
QuadEdge |
insertSite(Vertex v)
Inserts a new site into the Subdivision, connecting it to the vertices of the containing triangle (or quadrilateral, if the split point falls on an existing edge). |
boolean |
isFrameBorderEdge(QuadEdge e)
Tests whether a QuadEdge is an edge on the border of the frame facets and the internal facets. |
boolean |
isFrameEdge(QuadEdge e)
Tests whether a QuadEdge is an edge incident on a frame triangle vertex. |
boolean |
isFrameVertex(Vertex v)
Tests whether a vertex is a vertex of the outer triangle. |
boolean |
isOnEdge(QuadEdge e,
Coordinate p)
Tests whether a Coordinate lies on a QuadEdge , up to a
tolerance determined by the subdivision tolerance. |
boolean |
isVertexOfEdge(QuadEdge e,
Vertex v)
Tests whether a Vertex is the start or end vertex of a
QuadEdge , up to the subdivision tolerance distance. |
QuadEdge |
locate(Coordinate p)
Finds a quadedge of a triangle containing a location specified by a Coordinate , if one exists. |
QuadEdge |
locate(Coordinate p0,
Coordinate p1)
Locates the edge between the given vertices, if it exists in the subdivision. |
QuadEdge |
locate(Vertex v)
Finds a quadedge of a triangle containing a location specified by a Vertex , if one exists. |
QuadEdge |
locateFromEdge(Vertex v,
QuadEdge startEdge)
Locates an edge of a triangle which contains a location specified by a Vertex v. |
QuadEdge |
makeEdge(Vertex o,
Vertex d)
Creates a new quadedge, recording it in the edges list. |
void |
setLocator(QuadEdgeLocator locator)
Sets the QuadEdgeLocator to use for locating containing triangles
in this subdivision. |
void |
visitTriangles(TriangleVisitor triVisitor,
boolean includeFrame)
Visitors |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public QuadEdgeSubdivision(Envelope env, double tolerance)
env
- the bouding box to surroundtolerance
- the tolerance value for determining if two sites are equalMethod Detail |
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public static void getTriangleEdges(QuadEdge startQE, QuadEdge[] triEdge)
QuadEdge
.
startQE
- triEdge
-
java.lang.IllegalArgumentException
- if the edges do not form a trianglepublic double getTolerance()
public Envelope getEnvelope()
public java.util.Collection getEdges()
QuadEdge
s (one for every pair of
vertices which is connected).
public void setLocator(QuadEdgeLocator locator)
QuadEdgeLocator
to use for locating containing triangles
in this subdivision.
locator
- a QuadEdgeLocatorpublic QuadEdge makeEdge(Vertex o, Vertex d)
o
- d
-
public QuadEdge connect(QuadEdge a, QuadEdge b)
a
- b
-
public void delete(QuadEdge e)
e
- the quadedge to deletepublic QuadEdge locateFromEdge(Vertex v, QuadEdge startEdge)
This locate algorithm relies on the subdivision being Delaunay. For non-Delaunay subdivisions, this may loop for ever.
v
- the location to search forstartEdge
- an edge of the subdivision to start searching at
LocateFailureException
- if the location algorithm fails to converge in a reasonable
number of iterationspublic QuadEdge locate(Vertex v)
Vertex
, if one exists.
x
- the vertex to locate
public QuadEdge locate(Coordinate p)
Coordinate
, if one exists.
p
- the Coordinate to locate
public QuadEdge locate(Coordinate p0, Coordinate p1)
p0
- a coordinatep1
- another coordinate
public QuadEdge insertSite(Vertex v)
This method does NOT maintain the Delaunay condition. If desired, this must be checked and enforced by the caller.
This method does NOT check if the inserted vertex falls on an edge. This must be checked by the caller, since this situation may cause erroneous triangulation
v
- the vertex to insert
public boolean isFrameEdge(QuadEdge e)
e
- the edge to test
public boolean isFrameBorderEdge(QuadEdge e)
e
- the edge to test
public boolean isFrameVertex(Vertex v)
v
- the vertex to test
public boolean isOnEdge(QuadEdge e, Coordinate p)
Coordinate
lies on a QuadEdge
, up to a
tolerance determined by the subdivision tolerance.
e
- a QuadEdgep
- a point
public boolean isVertexOfEdge(QuadEdge e, Vertex v)
Vertex
is the start or end vertex of a
QuadEdge
, up to the subdivision tolerance distance.
e
- v
-
public java.util.Collection getVertices(boolean includeFrame)
Vertex
es in the subdivision,
including the frame vertices if desired.
includeFrame
- true if the frame vertices should be included
getVertexUniqueEdges(boolean)
public java.util.List getVertexUniqueEdges(boolean includeFrame)
QuadEdge
s whose origin
vertices are a unique set which includes
all vertices in the subdivision.
The frame vertices can be included if required.
This is useful for algorithms which require traversing the subdivision starting at all vertices. Returning a quadedge for each vertex is more efficient than the alternative of finding the actual vertices using {@link #getVertices) and then locating quadedges attached to them.
includeFrame
- true if the frame vertices should be included
public java.util.List getPrimaryEdges(boolean includeFrame)
QuadEdge
which occupies the 0'th position in its array of associated quadedges.
These provide the unique geometric edges of the triangulation.
includeFrame
- true if the frame edges are to be included
public void visitTriangles(TriangleVisitor triVisitor, boolean includeFrame)
public java.util.List getTriangleEdges(boolean includeFrame)
includeFrame
- true if the frame triangles should be included
public java.util.List getTriangleVertices(boolean includeFrame)
Vertex
es.
includeFrame
- true if the frame triangles should be included
public java.util.List getTriangleCoordinates(boolean includeFrame)
includeFrame
- true if the frame triangles should be included
public Geometry getEdges(GeometryFactory geomFact)
MultiLineString
containing 2-point lines.
geomFact
- the GeometryFactory to use
public Geometry getTriangles(GeometryFactory geomFact)
GeometryCollection
of triangular Polygon
s.
geomFact
- the GeometryFactory to use
public Geometry getVoronoiDiagram(GeometryFactory geomFact)
GeometryCollection
of Polygon
s
The userData of each polygon is set to be the {@link Coordinate) of the cell site. This allows easily associating external data associated with the sites to the cells.
geomFact
- a geometry factory
public java.util.List getVoronoiCellPolygons(GeometryFactory geomFact)
Polygon
s for the Voronoi cells
of this triangulation.
The userData of each polygon is set to be the {@link Coordinate) of the cell site. This allows easily associating external data associated with the sites to the cells.
geomFact
- a geometry factory
public Polygon getVoronoiCellPolygon(QuadEdge qe, GeometryFactory geomFact)
The userData of the polygon is set to be the {@link Coordinate) of the site. This allows attaching external data associated with the site to this cell polygon.
qe
- a quadedge originating at the cell sitegeomFact
- a factory for building the polygon
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JTS Topology Suite version 1.12 | ||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |