org.deegree.ogcwebservices.wpvs.utils
Class QuadTreeSplitter

java.lang.Object
  org.deegree.ogcwebservices.wpvs.utils.QuadTreeSplitter

public class QuadTreeSplitter
extends Object

The QuadTreeSplitter class can be used to create x-y axis alligned request quads from a qiven List of ResolutionStripe s. These Stripes depend on the ViewFrustrum and it's projection on the x-y plane (the so called footprint). To create an approximation of this footprint a Quadtree (a geometric spatial structure, which recursively divides a boundingbox into four containing boundingboxes) is built. The leafs of this tree are merged according to their resolution and size to create the requeststripes.

Version:

$Revision: 18195 $, $Date: 2009-06-18 17:55:39 +0200 (Do, 18. Jun 2009) $

Author:

Rutger Bezema, last edited by: $Author: mschneider $

Constructor Summary

QuadTreeSplitter(ArrayList<ResolutionStripe> resolutionStripes, double imageWidth, boolean highQuality)
Creates a new Quadtree, from the given resolutionstripes.

Method Summary

ArrayList<ResolutionStripe>	getRequestQuads(double extraRequestPercentage, int quadMergeCount) After instantiating a Quadtree, this method can be called to build the (x-y) axis-alligned request stripes.
void	outputTree(Graphics2D g2d) Outputs the tree

Methods inherited from class java.lang.Object

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

Constructor Detail

QuadTreeSplitter

public QuadTreeSplitter(ArrayList<ResolutionStripe> resolutionStripes,
                        double imageWidth,
                        boolean highQuality)

Creates a new Quadtree, from the given resolutionstripes. The resulting tree can be used to generate requeststripes which are (x-y) axis aligned.

The Quality argument is used for the recursive termination criteria, if it is set to true the requeststripes will accurately approximate the footprint (=projection of the viewfrustrum onto the ground) and the resolutions given in the resolutionstripes this results in a lot of requests which can slow down the wpvs. If set to false the footprint and the given resolutions will be approximated poorly but only a few requeststripes are created, resulting in a faster wpvs.

Parameters:

resolutionStripes - the different resolutionstripes.

imageWidth - the width of the target image, necessary for calculating the width resolution of the requeststripe.

highQuality - true if accurate (but many) requeststripes should be generated, false if none accurate (but only a few) requests should be generated.

Method Detail

getRequestQuads

public ArrayList<ResolutionStripe> getRequestQuads(double extraRequestPercentage,
                                                   int quadMergeCount)

After instantiating a Quadtree, this method can be called to build the (x-y) axis-alligned request stripes.

Parameters:

extraRequestPercentage - a percentage to be added to the resulting stripes ( a value between [0,1] ), which might correct gapes between stripes.WPVSDeegreeParams.getExtendRequestPercentage()

quadMergeCount - the number of leaves this splitter can have, before it starts merging leaves together WPVSDeegreeParams.getQuadMergeCount()

Returns:

the (x-y) axis-alligned request squares best fitted the given resolutionstripes.

outputTree

public void outputTree(Graphics2D g2d)

Outputs the tree

Parameters:

g2d - if the quadtree should be drawn.