spatialindex.java

openmap java写的开源数字地图程序. 用applet实现,可以像google map 那样放大缩小地图.

// **********************************************************************
// 
// <copyright>
// 
//  BBN Technologies
//  10 Moulton Street
//  Cambridge, MA 02138
//  [phone]
// 
//  Copyright (C) BBNT Solutions LLC. All rights reserved.
// 
// </copyright>
// **********************************************************************
// 
// $Source: /cvs/distapps/openmap/src/openmap/com/bbn/openmap/layer/shape/SpatialIndex.java,v $
// $RCSfile: SpatialIndex.java,v $
// $Revision: 1.6.2.4 $
// $Date: 2005/08/09 21:17:47 $
// $Author: dietrick $
// 
// **********************************************************************

package com.bbn.openmap.layer.shape;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintStream;
import java.util.Vector;

import javax.swing.ImageIcon;

import com.bbn.openmap.io.BinaryBufferedFile;
import com.bbn.openmap.io.BinaryFile;
import com.bbn.openmap.io.Closable;
import com.bbn.openmap.io.FormatException;
import com.bbn.openmap.util.Debug;

/**
 * A Spatial Index is a variation on a Shape Index, adding the
 * bounding box of the shape to the index.
 * <p>
 * The file has a 100 byte header identical to a Shape Index followed
 * by <i>n </i> records.
 * <p>
 * The record layout of the spatial index is as follows:
 * <p>
 * <TABLE BORDER COLS=5 WIDTH="100%" >
 * <TR>
 * <TD ALIGN=CENTER><b><i>Position </i> </b></TD>
 * <TD ALIGN=CENTER><b><i>Field </i> </b></TD>
 * <TD ALIGN=CENTER><b><i>Value </i> </b></TD>
 * <TD ALIGN=CENTER><b><i>Type </i> </b></TD>
 * <TD ALIGN=CENTER><b><i>Byte Order </i> </b></TD>
 * </TR>
 * <TR>
 * <TD ALIGN=CENTER>Byte 0</TD>
 * <TD ALIGN=CENTER>Offset</TD>
 * <TD ALIGN=CENTER>Offset</TD>
 * <TD ALIGN=CENTER>Integer</TD>
 * <TD ALIGN=CENTER>Big</TD>
 * </TR>
 * <TR>
 * <TD ALIGN=CENTER>Byte 4</TD>
 * <TD ALIGN=CENTER>Content Length</TD>
 * <TD ALIGN=CENTER>Content Length</TD>
 * <TD ALIGN=CENTER>Integer</TD>
 * <TD ALIGN=CENTER>Big</TD>
 * </TR>
 * <TR>
 * <TD ALIGN=CENTER>Byte 8</TD>
 * <TD ALIGN=CENTER>Bounding Box</TD>
 * <TD ALIGN=CENTER>Xmin</TD>
 * <TD ALIGN=CENTER>Double</TD>
 * <TD ALIGN=CENTER>Little</TD>
 * </TR>
 * <TR>
 * <TD ALIGN=CENTER>Byte 16</TD>
 * <TD ALIGN=CENTER>Bounding Box</TD>
 * <TD ALIGN=CENTER>Ymin</TD>
 * <TD ALIGN=CENTER>Double</TD>
 * <TD ALIGN=CENTER>Little</TD>
 * </TR>
 * <TR>
 * <TD ALIGN=CENTER>Byte 24</TD>
 * <TD ALIGN=CENTER>Bounding Box</TD>
 * <TD ALIGN=CENTER>Xmax</TD>
 * <TD ALIGN=CENTER>Double</TD>
 * <TD ALIGN=CENTER>Little</TD>
 * </TR>
 * <TR>
 * <TD ALIGN=CENTER>Byte 32</TD>
 * <TD ALIGN=CENTER>Bounding Box</TD>
 * <TD ALIGN=CENTER>Ymax</TD>
 * <TD ALIGN=CENTER>Double</TD>
 * <TD ALIGN=CENTER>Little</TD>
 * </TR>
 * </TABLE>
 * 
 * <H2>Usage</H2>
 * <DT>java com.bbn.openmap.layer.shape.SpatialIndex -d file.ssx
 * </DT>
 * <DD><i>Dumps spatial index information, excluding bounding boxes
 * to stdout. Useful for comparing to a shape index. </i></DD>
 * <p>
 * <DT>java com.bbn.openmap.layer.shape.SpatialIndex -d -b file.ssx
 * </DT>
 * <DD><i>Dumps spatial index information including bounding boxes to
 * stdout. </i></DD>
 * <p>
 * <DT>java com.bbn.openmap.layer.shape.SpatialIndex -c file.ssx
 * file.shp</DT>
 * <DD><i>Creates spatial index <code>file.ssx</code> from shape
 * file <code>file.shp</code>. </i></DD>
 * <p>
 * 
 * <H2>Notes</H2>
 * When reading the Shape file, the content length is the length of
 * the record's contents, exclusive of the record header (8 bytes). So
 * the size that we need to read in from the Shape file is actually
 * denoted as ((contentLength * 2) + 8). This converts from 16bit
 * units to 8 bit bytes and adds the 8 bytes for the record header.
 * 
 * <H2>To Do</H2>
 * <UL>
 * <LI>index arcs</LI>
 * <LI>index multipoints</LI>
 * </UL>
 * 
 * @author Tom Mitchell <[e-mail]>
 * @version $Revision: 1.6.2.4 $ $Date: 2005/08/09 21:17:47 $
 * @see ShapeIndex
 */
public class SpatialIndex extends ShapeUtils implements Closable {

    /** Size of a shape file header in bytes. */
    public final static int SHAPE_FILE_HEADER_LENGTH = 100;

    /** Size of a shape file record header in bytes. */
    public final static int SHAPE_RECORD_HEADER_LENGTH = 8;

    /** Size of the spatial index header in bytes. */
    public final static int SPATIAL_INDEX_HEADER_LENGTH = 100;

    /** Size of the spatial index record in bytes. */
    public final static int SPATIAL_INDEX_RECORD_LENGTH = 40;

    /** Default size for shape record buffer. */
    public final static int DEFAULT_SHAPE_RECORD_SIZE = 50000;

    /** The spatial index file. */
    protected BinaryBufferedFile ssx;

    /** The shape file. */
    protected BinaryBufferedFile shp;

    /** The icon to use for point objects. */
    protected ImageIcon pointIcon;

    /** The bounds of all the shapes in the shape file. */
    protected ESRIBoundingBox bounds = null;

    /**
     * Opens a spatial index file for reading.
     * 
     * @param ssxFilename the name of the spatial index file
     * @exception IOException if something goes wrong opening the file
     */
    public SpatialIndex(String ssxFilename) throws IOException {
        ssx = new BinaryBufferedFile(ssxFilename);
    }

    /**
     * Opens a spatial index file and it's associated shape file.
     * 
     * @param ssxFilename the name of the spatial index file
     * @param shpFilename the name of the shape file
     * @exception IOException if something goes wrong opening the
     *            files
     */
    public SpatialIndex(String ssxFilename, String shpFilename)
            throws IOException {
        if (Debug.debugging("spatialindex")) {
            Debug.output("SpatialIndex(" + ssxFilename + ", " + shpFilename
                    + ");");
        }

        ssx = new BinaryBufferedFile(ssxFilename);
        shp = new BinaryBufferedFile(shpFilename);
    }

    /**
     * Get the box boundary containing all the shapes.
     */
    public ESRIBoundingBox getBounds() {
        if (bounds == null) {
            try {
                locateRecords(-180, -90, 180, 90);
            } catch (IOException ioe) {
                bounds = null;
            } catch (FormatException fe) {
                bounds = null;
            }
        }
        return bounds;
    }

    /**
     * Reset the bounds so they will be recalculated the next time a
     * file is read.
     */
    public void resetBounds() {
        bounds = null;
    }

    /**
     * Creates a record instance from the shape file data. Calls the
     * appropriate record constructor based on the shapeType, and
     * passes the buffer and offset to that constructor.
     * 
     * @param shapeType the shape file's shape type, enumerated in
     *        <code>ShapeUtils</code>
     * @param b the buffer pointing to the raw record data
     * @param off the offset of the data starting point in the buffer
     * @exception IOException if something goes wrong reading the file
     * @see ShapeUtils
     */
    public ESRIRecord makeESRIRecord(int shapeType, byte[] b, int off)
            throws IOException {
        switch (shapeType) {
        case SHAPE_TYPE_NULL:
            return null;
        case SHAPE_TYPE_POINT:
            //          return new ESRIPointRecord(b, off);
            return new ESRIPointRecord(b, off, pointIcon);
        case SHAPE_TYPE_POLYGON:
        case SHAPE_TYPE_ARC:
            //      case SHAPE_TYPE_POLYLINE:
            return new ESRIPolygonRecord(b, off);
        case SHAPE_TYPE_MULTIPOINT:
            Debug.output("SpatialIndex.makeESRIRecord: Arc NYI");
            return null;
        //          return new ESRIMultipointRecord(b, off);
        default:
            return null;
        }
    }

    /**
     * Locates records in the shape file that intersect with the given
     * rectangle. The spatial index is searched for intersections and
     * the appropriate records are read from the shape file.
     * 
     * @param xmin the smaller of the x coordinates
     * @param ymin the smaller of the y coordinates
     * @param xmax the larger of the x coordinates
     * @param ymax the larger of the y coordinates
     * @return an array of records that intersect the given rectangle
     * @exception IOException if something goes wrong reading the
     *            files
     */
    public ESRIRecord[] locateRecords(double xmin, double ymin, double xmax,
                                      double ymax) throws IOException,
            FormatException {

        boolean gatherBounds = false;

        if (bounds == null) {
            bounds = new ESRIBoundingBox();
            gatherBounds = true;
        }

        if (Debug.debugging("spatialindex")) {
            Debug.output("locateRecords:");
            Debug.output("\txmin: " + xmin + "; ymin: " + ymin);
            Debug.output("\txmax: " + xmax + "; ymax: " + ymax);
        }

        byte ixRecord[] = new byte[SPATIAL_INDEX_RECORD_LENGTH];
        int recNum = 0;
        Vector v = new Vector();
        int sRecordSize = DEFAULT_SHAPE_RECORD_SIZE;
        byte sRecord[] = new byte[sRecordSize];

        // Need to figure out what the shape type is...
        ssx.seek(32);