vhtransform.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/util/VHTransform.java,v $
// $RCSfile: VHTransform.java,v $
// $Revision: 1.3.2.1 $
// $Date: 2004/10/14 18:27:46 $
// $Author: dietrick $
// 
// **********************************************************************

package com.bbn.openmap.util;

/* Cathleen Lancaster - 6 Hutcheson */

/**
 * The VH coordinate system is used by ATT to compute distance used in
 * determining phone call costs.
 * <P>
 * 
 * VH coordinates can be used to compute distance simply, see
 * distance().
 * <P>
 * 
 * This code is based on C code provided by the authors mentioned
 * below, as well as Lisp code by Larry Denenberg of BBN.
 * <P>
 * 
 * I have ported this code to Java, unified the forward and inverse
 * transformations and added some comments. I've left basic code and
 * comments mostly intact.
 * <P>
 * 
 * The url's to the original emails are:
 * <P>
 * 
 * http://x11.dejanews.com/getdoc.xp?AN=177302113&CONTEXT=895858362.931528704&hitnum=1
 * <BR>
 * http://x11.dejanews.com/getdoc.xp?AN=223540739&CONTEXT=895858362.931528704&hitnum=5
 */
public class VHTransform {
    /* Polynomial constants */
    public static final double K1 = .99435487;
    public static final double K2 = .00336523;
    public static final double K3 = -.00065596;
    public static final double K4 = .00005606;
    public static final double K5 = -.00000188;

    /* PI in various forms */
    public static final double M_PI_2 = Math.PI / 2.0;

    /*
     * spherical coordinates of eastern reference point EX^2 + EY^2 +
     * EZ^2 = 1
     */
    public static final double EX = .40426992;
    public static final double EY = .68210848;
    public static final double EZ = .60933887;

    /*
     * spherical coordinates of western reference point WX^2 + WY^2 +
     * WZ^2 = 1
     */
    public static final double WX = .65517646;
    public static final double WY = .37733790;
    public static final double WZ = .65449210;

    /* spherical coordinates of V-H coordinate system */
    /* PX^2 + PY^2 + PZ^2 = 1 */
    public static final double PX = -0.555977821730048699;
    public static final double PY = -0.345728488161089920;
    public static final double PZ = 0.755883902605524030;

    /* Rotation by 76 degrees */
    public final static double rot = radians(76.597497064);
    public final static double ROTC = Math.cos(rot);
    public final static double ROTS = Math.sin(rot);

    public static double radians(double degrees) {
        return degrees * Math.PI / 180.0;
    }

    public static double degrees(double radians) {
        return radians * 180.0 / Math.PI;
    }

    /* orthogonal translation values */
    public static final double TRANSV = 6363.235;
    public static final double TRANSH = 2250.700;

    /** radius of earth in sqrt(0.1)-mile units, minus 0.3 percent */
    public static final double RADIUS = 12481.103;

    public static final double K9 = RADIUS * ROTC;
    public static final double K10 = RADIUS * ROTS;

    public VHTransform() {}

    /** Return the V corresponding to the most recent toVH(). * */
    public double getV() {
        return this.resultV;
    }

    /** Return the H corresponding to the most recent toVH(). * */
    public double getH() {
        return this.resultH;
    }

    /**
     * Return the latitude corresponding to the most recent
     * toLatLon(). *
     */
    public double getLat() {
        return this.resultLat;
    }

    /**
     * Return the longitude corresponding to the most recent
     * toLatLon(). *
     */
    public double getLon() {
        return this.resultLon;
    }

    /** Return the distance in miles between 2 VH pairs. * */
    public static double distance(double v1, double h1, double v2, double h2) {
        double dv = v2 - v1;
        double dh = h2 - h1;
        // Was
        //      return Math.sqrt(dv*dv + dh*dh)/10.0;
        // Now, thanks to Andrew Canfield
        return Math.sqrt((dv * dv + dh * dh) / 10.0);
    }

    private double resultV = 0.0;
    private double resultH = 0.0;
    private double resultLat = 0.0;
    private double resultLon = 0.0;

    /*
     * 
     * Subject: Re: AT&T V-H Coordinates From: [e-mail]
     * (Tim Shoppa) Date: 1996/08/28 Message-ID:
     * <[e-mail]> Newsgroups:
     * comp.dcom.telecom [More Headers] [Subscribe to
     * comp.dcom.telecom]
     * 
     * In article <[e-mail]>, Drew Larsen
     * <[e-mail]> wrote:
     *  > Ok folks, scratch your heads and see if you can remember how
     * to > translate a point on the earth measured in
     * latitude/longitude to the > commonly used V&H system used in
     * the telecom industry.
     * 
     * Below is a past post by Stu Jeffery containing a program which
     * does the conversion the other way. If anybody is willing to buy
     * me a nice lunch (my standard fee for two dimensional function
     * inversion), I'll modify it to go both ways :-)
     * 
     * Tim Shoppa, TRIUMF theory group | Internet: [e-mail]
     * TRIUMF, Canada's National Meson Facility | Voice: 604-222-1047
     * loc 6446 4004 WESBROOK MALL, UBC CAMPUS | FAX: [phone]
     * University of British Columbia, Vancouver, B.C., CANADA V6T 2A3
     * 
     * Article: 54928 of comp.dcom.telecom Date: Tue, 29 Aug 1995
     * 00:16:38 -0800 From: [e-mail] (Stu Jeffery)
     * Subject: Re: V&H Questions Message-ID:
     * <[e-mail]> X-Telecom-Digest: Volume 15,
     * Issue 362, Message 11 of 11
     * 
     * Attached is a C program that will do what you want. I don't
     * know anything more than what is here. I think it was posted in
     * a news group, so use at your own legal risk. I have compiled it
     * and it works fine.
     * 
     * Going the other way is a bit more complicated. Probably the
     * simplest way is by successive approximation.
     * 
     * Good Luck.
     * 
     * -----------------------------------------
     */

    /**
     * Computes Bellcore/AT&T V & H (vertical and horizontal)
     * coordinates from latitude and longitude. Used primarily by
     * local exchange carriers (LEC's) to compute the V & H
     * coordinates for wire centers.
     * <P>
     * 
     * This is an implementation of the Donald Elliptical Projection,
     * a Two-Point Equidistant projection developed by Jay K. Donald
     * of AT&T in 1956 to establish long-distance telephone rates.
     * (ref: "V-H Coordinate Rediscovered", Eric K. Grimmelmann, Bell
     * Labs Tech. Memo, 9/80. (References Jay Donald notes of Jan 17,
     * 1957.)) Ashok Ingle of Bellcore also wrote an internal memo on
     * the subject.
     * <P>
     * 
     * The projection is specially modified for the ellipsoid and is
     * confined to the United States and southern Canada.
     * <P>
     * 
     * Derived from a program obtained from an anonymous author within
     * Bellcore by way of the National Exchange Carrier Association.
     * Cleaned up and improved a bit by Tom Libert ([e-mail],
     * [e-mail]).
     * <P>
     * 
     * CASH REWARD for copies of the reference papers, or for an