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    Re: Map of the "Age of the Tides"
    From: Glendon
    Date: 2004 Jan 13, 10:30 +1100

    ----- Original Message -----
    From: Frank Reed
    To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM
    Sent: Tuesday, January 13, 2004 9:05 AM
    Subject: Map of the "Age of the Tides"
    
    
    Well, it took some digging, but I managed to find a set of global tidal
    harmonics despite the UKHO's diligent efforts to expunge them from the
    Internet. [Ya see, there are certain old software libraries that can be
    found on the net but they're not hooked into the WWW, and those libraries
    include old DOS shareware that has never been indexed on the web so the UKHO
    never found them and never managed to issue one of their cease-and-desist
    orders].
    
    ----------------------------------------------------------------------------
    ---------------
    I am well and truly out of my depth in the discussions of tides on this
    list.  So its with some trepidation that I note that I found the above a bit
    hard to understand, with its implication that UKHO controls global tide
    data. There are many tidal prediction programs available....based on tidal
    harmonics supplemented by local data. XTide and its many variants being
    examples. On the WXTide32  site I find a news item:
    
    May 2001: I was notified by the United Kingdom Hydrographic Office (UKHO)
    that the Crown claimed copyright ownership of all tidal products for Great
    Britain, Ireland and Scotland. To avoid being sued, my options were to stop
    distributing tidal data for those areas or purchase a license (with a
    recurring fee) for use of the official UKHO data. WXTide32 has never been a
    commercial endeavor so I declined their offer of buying a license. It
    appears that when the International Hydrographic Office (IHO) withdrew the
    IHO Tidal Constituent database in 1999, tidal data ownership reverted to
    individual countries and the blanket approval IHO gave for non-commercial
    use of world-wide tidal data was rescinded. Since Great Britain has now
    claimed copyright ownership, other countries may follow suit. This means
    that only tidal data for countries that have explicitly released their data
    to public domain may be used free of risk of copyright infringement. Data
    for the U.S. is not a problem. That data was gathered using public
    (taxpayer) funds so no copyright is or can be attached to NOS or NOA tidal
    data. That still leaves lots of world though, and the database now
    distributed with WXTide32 version 2.7 shows that new greatly reduced area of
    coverage.
    
    Also on the site is a later news item:
    
    January 2004: Hackers took over my guestbook and contact scripts last month
    so those scripts were disabled. I hope the new contact email is more
    hack-resistant.
    I was notified that the IHO was not disbanded when their web site and email
    vanished for an extended period of time.
    A non-governmental source for U.K, Ireland and Scotland tide data might have
    been found. I will keep you posted.
    The next version is in process. Please don't give up hope.
    
    The data files for XTide and its variants (called ports, because the
    original XTide was for Unix machines) are available on the various sites.
    
    Lee Martin
    
    
    

       
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