wpttrackdistance.java

基于Java的地图数据管理软件。使用MySQL数据库管理系统。

package net.aetherial.gis.publicuse;

import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import net.aetherial.gis.surface.ItemValue;
/**
 * <p>Title: </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2004</p>
 *
 * <p>Company: </p>
 *
 * @author not attributable
 * @version 1.0
 */
public class WptTrackDistance {
  public WptTrackDistance() {
  }



  /**
   * 得到航点到指定线段的距离
   * 返回的不是实际距离
   */
  public static double getWptToTrackPointsDis(Node wpt,Node trackPoint1,Node trackPoint2){
    if (wpt == null || trackPoint1 == null || trackPoint2 == null) {
      return Double.MAX_VALUE;
    }

    PointLineDistance pd = new PointLineDistance();
    pd.setPoint0(Double.parseDouble(ItemValue.getWaypointX(wpt)), Double.parseDouble(ItemValue.getWaypointY(wpt)));
    pd.setPoint1(Double.parseDouble(ItemValue.getTracksPointX(trackPoint1)), Double.parseDouble(ItemValue.getTracksPointY(trackPoint1)));
    pd.setPoint2(Double.parseDouble(ItemValue.getTracksPointX(trackPoint2)), Double.parseDouble(ItemValue.getTracksPointY(trackPoint2)));
    return pd.getDis();
  }


  /**
   * 得到航点到指定线段的距离
   * 返回的不是实际距离
   */
  public static double getWptToTrackDis(Node wpt,Node track){
    if (wpt == null || track == null) {
      return Double.MAX_VALUE;
    }
    NodeList nl = ItemValue.getTracksPoint(track);
    if (nl == null) {
      return Double.MAX_VALUE;
    }
    PointLineDistance pd;
    double temp = Double.MAX_VALUE;
    for (int i = 0; i < nl.getLength()-1; i++) {
      pd = new PointLineDistance();
      pd.setPoint0(Double.parseDouble(ItemValue.getWaypointX(wpt)),
                   Double.parseDouble(ItemValue.getWaypointY(wpt)));
      pd.setPoint1(Double.parseDouble(ItemValue.getTracksPointX(nl.item(i))),
                   Double.parseDouble(ItemValue.getTracksPointY(nl.item(i))));
      pd.setPoint2(Double.parseDouble(ItemValue.getTracksPointX(nl.item(i+1))),
                   Double.parseDouble(ItemValue.getTracksPointY(nl.item(i+1))));
      temp = Math.min(temp,pd.getDis());
    }
    return temp;
  }

}