org.opentripplanner.common.geometry

Class DelaunayIsolineBuilder<TZ>

java.lang.Object

org.opentripplanner.common.geometry.DelaunayIsolineBuilder<TZ>

All Implemented Interfaces:

IsolineBuilder<TZ>

public class DelaunayIsolineBuilder<TZ>
extends Object
implements IsolineBuilder<TZ>

Compute isoline based on a Delaunay triangulation of z samplings. It will compute an isoline for a given z0 value. The isoline is composed of a list of n polygons, CW for normal polygons, CCW for "holes". The isoline computation can be called multiple times on the same builder for different z0 value: this will reduce the number of Fz sampling as they are cached in the builder, and reduce the number of time the Delaunay triangulation has to be built. The algorithm is rather simple: for each edges of the triangulation check if the edge is "cutting" (ie crossing the z0 plane). Then start for each unprocessed cutting edge using a walk algorithm, keeping high z0 always one the same side, to build a set of closed polygons. Then process each polygons to punch holes: a CW polygon is a hole in a larger CCW polygon, a CCW polygon is an islan (shell).

Author:

laurent

Nested Class Summary

Nested classes/interfaces inherited from interface org.opentripplanner.common.geometry.IsolineBuilder

IsolineBuilder.ZMetric<TZ>

Constructor Summary

Constructors

Constructor and Description
DelaunayIsolineBuilder(DelaunayTriangulation<TZ> triangulation, IsolineBuilder.ZMetric<TZ> zMetric) Create an object to compute isolines.

Method Summary

Modifier and Type	Method and Description
com.vividsolutions.jts.geom.Geometry	computeIsoline(TZ z0)
com.vividsolutions.jts.geom.Geometry	getDebugGeometry()
void	setDebug(boolean debug)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DelaunayIsolineBuilder

public DelaunayIsolineBuilder(DelaunayTriangulation<TZ> triangulation,
                              IsolineBuilder.ZMetric<TZ> zMetric)

Create an object to compute isolines. One may call several time computeIsoline on the same object, with different z0 values.

Parameters:

triangulation - The triangulation to process. Must be closed (no edge at the border should intersect).

zMetric - The Z metric (intersection detection and interpolation method).

Method Detail

setDebug

public void setDebug(boolean debug)

computeIsoline

public com.vividsolutions.jts.geom.Geometry computeIsoline(TZ z0)

Specified by:

computeIsoline in interface IsolineBuilder<TZ>

getDebugGeometry

public final com.vividsolutions.jts.geom.Geometry getDebugGeometry()