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I had asked for conversion algorithms between lat/long and UTM.

Paul Hirose is always reliable, and I was interested in his message-

>The "Explanatory Supplement to the Astronomical Almanac" also has the
>formulas, in a different format as I recall. Several years ago I tried
>to code up a routine based on that book, but never got it to work.
>Later someone told me the book had a misprint.

Especially as I had that volume (Siedelmann) on my shelves. It has the
conversion formulae that were exactly what I was looking for. I have coded
up one part of the conversion (lat/long to UTM but not yet vice versa) in
Basic on a pocket calculator, ready to test. I have taken heed of Paul's
warning about a misprint. If he can recall anything about that misprint, or
in what way the problem showed up, it would be good to learn more.

Vic Fraenckel said-

>download GeoCalc from www.windreader.com/geodesy and be done with it.

Well, good advice perhaps, but is a version available that will run on my
old Mac?

However, I'm a chap who prefers to do his own coding, if possible, rather
than accept what others have done. In that way, you get to learn more about
what's going on inside, and get the freedom to tinker and modify, which I
often enjoy. Of course, that then opens the question "well, how do you know
the original algoriths are correct?", which is relevant particularly to the
present case, in which Paul suspects a misprint. I might need to follow
that up in the original papers that Seidelmann refers to.

George.


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