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    Re: ONC Charts online
    From: Frank Reed CT
    Date: 2003 Dec 9, 16:02 EST
    Fredrik wrote:
    "I've found this GLOBE project from a web search, which offers free
    "30-arc-second (1-km) gridded, quality-controlled global Digital
    Elevation Model (DEM)" data."

    That was the best you could get until this year.

    GLOBE and the similar product GTOPO30 were based on traditional mapping and elevation resources (scanned maps). They had numerous errors and inconsistencies. They have been superceded by data from one of the most important space shuttle missions ever --the shuttle radar topography mission. A version of this data set was released just a few months ago. Search for SRTM30 to read more about it.

    If you go to my web site and click on the link at the very bottom on the left that says "Waterworld", you'll see one use for this sort of data, though I don't think it has much relevance to marine navigation.

    Frank E. Reed
    [ ] Mystic, Connecticut
    [X] Chicago, Illinois
       
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