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    Re: 1906 Bowditch
    From: Frank Reed
    Date: 2007 Aug 17, 02:02 -0400

    George, you wrote:
    "But I can see a snag here. If you requested a search for "LUNAR DISTANCES",
    presumably, because of that hiccup in the OCR scan, it wouldn't take you to
    that appendix.
    However, if you happened to search for "LTJNAE DISTANCES", then it would."
    OCR of scans like these is better than 95% accurate. So if you search for
    "lunar" and the word is garbled 5% of the time, you will miss occasional
    isolated references. But if you're trying to find whole passages referencing
    lunars, then there's a good chance that you will find it. For example, that
    appendix contains the phrase 'lunar distance' more than once, so you would
    find it even though the section heading is garbled.
    OCR software typically works well on paragraphs of cleanly scanned text in a
    single typeface. It does less well on titles and individual words in unusual
    fonts. It performs poorly on math and tabular information. But it's much
    better than even the best paper index for a book since you can search for
    phrases that may not have seemed relevant to the original publishers of the
    book. And of course the search can be extended across the entire collection
    of scanned documents.
    You mentioned broadband. You may find that you can get something interesting
    from google books thanks to the new features which I mentioned in the
    previous message. Try this link:
    It should take you to the hyperlinked table of contents of the 1906
    Bowditch. I would guess that this page should load in less than 30 seconds
    even on a dialup line. Then scroll down to the bottom of the contents and
    you'll see a link to Appendix V "Lunar Distances" (by the way, this is
    nothing more than the standard treatment of Chauvenet's method which was
    included in the USN-revised Bowditch after 1880 --if it doesn't interest
    you, try one of the other chapters, e.g. "Longitude"). Additional pages
    should load even faster. Downloading the whole book would be prohibitive on
    a dialup line, but you should be able to read shorter sections this way.
    Note that the link above automatically sets the display to a plain image
    rather than the PDF document which should lessen the overhead somewhat. If
    you want to switch to the OCRed text, click the link that says "View plain
    text" towards the upper right.
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