NavList:

Wolfgang, you wrote:
"You're right, Frank. That guy is only the head of HMNAO, so most probably doesn't know what he is talking about, because he is only gazing at the stars. "

You raise a good point. Once upon a time, Her Majesty's Nautical Almanac Office was exceedingly important both in theoretical astronomy and practical navigation. As I put it (with intentional melodrama) in a recent talk, "two centuries ago, astronomy was one of the sinew's of empire". Two hundred years ago or even fifty years ago, the head of HMNAO would have been one of the world's unquestioned experts in all areas of navigation. But today, HMNAO is a very minor operation with very little value to the world. It is a shadow of its former self, and undoubtedly even its (probably very modest) budget is questioned every year. Is it surprising that the head of HMNAO would be boosting its value?? And is it likely that he would present genuinely professional knowledge of inertial navigation systems?

But this is all secondary to my original point here. This is a PDF of the guy's POWERPOINT SLIDES. Assuming that a line from any PowerPoint slide is anything more than a rough approximation to the speaker's point is dangerous. PowerPoint is evil. It creates the illusion of displaying distilled "facts", line by line, one "fact" after another. Somehow these slides have a hypnotic effect on audiences, even those removed from the original presentation, like NavList members following along today. The terse words and simple diagrams, crammed together in slides in an often gaudy and confusing fashioned, are interpreted like "tea leaves" while the original presentation and meaning may have been quite different. These slides are "hints" and no more.

By the way, if you do an Internet search on the phrase "PowerPoint is evil", you'll find much interesting debate, a lot of it going back to Edward Tufte (see a rendition of his PowerPoint version of the Gettysburg Address starting here: http://www.norvig.com/Gettysburg/sld001.htm). And here's a blog post from a couple of years ago that I found interesting reading:
http://blogs.hbr.org/silverman/2010/04/powerpoint-is-evil-redux.html.

-FER

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