llxyloader.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/proj/LLXYLoader.java,v $
// $RCSfile: LLXYLoader.java,v $
// $Revision: 1.1.2.3 $
// $Date: 2005/08/11 21:03:19 $
// $Author: dietrick $
// 
// **********************************************************************

package com.bbn.openmap.proj;

import com.bbn.openmap.LatLonPoint;
import com.bbn.openmap.util.PropUtils;
import com.bbn.openmap.util.Debug;

import java.util.Properties;

/**
 * ProjectionLoader to add the LLXY projection to an OpenMap
 * application.
 * 
 * @see BasicProjectionLoader
 */
public class LLXYLoader extends BasicProjectionLoader implements
        ProjectionLoader {

    public LLXYLoader() {
        super(LLXY.class,
              LLXY.LLXYName,
              "Equivalent projection, used for many web data sources.");
    }

    /**
     * Create the projection with the given parameters.
     * 
     * @throws exception if a parameter is missing or invalid.
     */
    public Projection create(Properties props) throws ProjectionException {

        try {
            LatLonPoint llp = (LatLonPoint) props.get(ProjectionFactory.CENTER);
            float scale = PropUtils.floatFromProperties(props,
                    ProjectionFactory.SCALE,
                    10000000);
            int height = PropUtils.intFromProperties(props,
                    ProjectionFactory.HEIGHT,
                    100);
            int width = PropUtils.intFromProperties(props,
                    ProjectionFactory.WIDTH,
                    100);
            return new LLXY(llp, scale, width, height);

        } catch (Exception e) {
            if (Debug.debugging("proj")) {
                Debug.output("LLXYLoader: problem creating LLXY projection "
                        + e.getMessage());
            }
        }

        throw new ProjectionException("LLXYLoader: problem creating LLXY projection");

    }

}