Application: gvSIG desktop » gvSIG tools: ToolBox

package es.unex.sextante.closestpts;

import java.util.List;

import com.vividsolutions.jts.geom.Coordinate;

import com.vividsolutions.jts.geom.Envelope;

import com.vividsolutions.jts.geom.Geometry;

import com.vividsolutions.jts.index.strtree.STRtree;

import es.unex.sextante.core.ITaskMonitor;

import es.unex.sextante.core.Sextante;

import es.unex.sextante.dataObjects.IFeature;

import es.unex.sextante.dataObjects.IFeatureIterator;

import es.unex.sextante.dataObjects.IVectorLayer;

import es.unex.sextante.exceptions.IteratorException;

public class NearestNeighbourFinder {

   private final STRtree m_Tree;

   private final int     m_iPoints;

   private final double  m_dX[];

   private final double  m_dY[];

   private final double  m_dZ[];

   public NearestNeighbourFinder(final IVectorLayer layer,

                                 final int iField,

                                 final ITaskMonitor task) throws IteratorException {

      int i;

      float x, y;

      task.setProgressText(Sextante.getText("Creating_index"));

      m_Tree = new STRtree();

      m_iPoints = layer.getShapesCount();

      m_dX = new double[m_iPoints];

      m_dY = new double[m_iPoints];

      m_dZ = new double[m_iPoints];

      i = 0;

      final IFeatureIterator iter = layer.iterator();

      while (iter.hasNext() && !task.isCanceled()) {

         final IFeature feature = iter.next();

         final Geometry geom = feature.getGeometry();

         final Coordinate coord = geom.getCoordinate();

         x = (float) coord.x;

         y = (float) coord.y;

         final Envelope bounds = geom.getEnvelopeInternal();

         m_Tree.insert(bounds, new Integer(i));

         m_dX[i] = x;

         m_dY[i] = y;

         try {

            m_dZ[i] = Double.parseDouble(feature.getRecord().getValue(iField).toString());

         }

         catch (final NumberFormatException e) {

            m_dZ[i] = 0;

         }

         if (i % 50 == 0) {

            task.setProgress(i, m_iPoints);

         }

         i++;

      }

      iter.close();

   }

   public PtAndDistance[] getClosestPoints(final double x,

                                           final double y,

                                           final double dDistance) {

      int i;

      int iID;

      double dDist;

      final Coordinate pt = new Coordinate(x, y);

      final Envelope search = new Envelope(pt);

      search.expandBy(dDistance);

      final List<Integer> list = m_Tree.query(search);

      final int iSize = list.size();

      final PtAndDistance pts[] = new PtAndDistance[iSize];

      for (i = 0; i < iSize; i++) {

         iID = list.get(i).intValue();

         dDist = pt.distance(new Coordinate(m_dX[iID], m_dY[iID]));

         pts[i] = new PtAndDistance(new Point3D(m_dX[iID], m_dY[iID], m_dZ[iID]), dDist);

      }

      return pts;

   }

}