NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Map of the "Age of the Tides"
From: Glendon
Date: 2004 Jan 13, 10:30 +1100
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reverted to individual countries and the blanket approval IHO gave for non-commercial use of world-wide tidal data was rescinded.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