value of GRAD angle mode, thought experiment

[Valentin Albillo]

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Hi, Didier Lachieze, Massimo Gnerucci, Maximilian Hohmann and Ángel Martin, {all highlighting and links are mine}

Didier Lachieze Wrote:@Valentin, thanks for sharing the HP survey from 45 years ago, that’s very interesting!

Thanks for your appreciation and kind words, Didier, I was very very young when HP sent me that Survey, not even in my 20's, and I felt quite honored and intrigued, so many questions ! A new top-of-the-line calculator in the works, surely surpassing my beloved HP-67's capabilities by far !!

Massimo Gnerucci Wrote:

Valentin Albillo Wrote:[...] have a look at this [HP survey] I completed and sent back to HP in July, 1977, more than 45 years ago. [...] The result of all this ? Most likely the HP-41C and its many peripherals.

Probably so, but you also killed the 95C.

Good riddance ! If I contributed ever so slightly to the HP-41 system being brought into existence instead of the stillborn HP-95C, so much the better.

Maximilian Hohmann Wrote:By the way: "financial" functions wouldn't have been worth a single Cent either

Yet financial functions can be used to very good effect, see for example HP-12C Serendipitous Solver, which is an 8-page article for the HP-12C financial calculator, featuring a 37-step program which makes use of the built-in microcode IRR solver and a number of assorted financial functions to find real roots of polynomials up to 14^th-degree (and up to 1480^th-degree or more if there are groups of repeated coefficients).

Both root finding and polynomial evaluation are implemented using built-in financial functions without user-code loops or branching, so it's the fastest and more convenient polynomial root solver for the whole Voyager Series calculators, greatly surpassing even the HP-15C's SOLVE function in this regard.

Ángel Martín Wrote:My understanding is that GRAD was very meaningful for surveyors, to the point of being a must. [...] Also surveyors probably don't qualify for your survey since they typically have a large budget.

If HP included GRAD to try and appeal to surveyors, they should also have included MIL, to try and appeal to the Military, as it's an angular measure (mil) used in many countries for land mapping and artillery, quoting from Wikipedia:

"For instance there are artillery sights and compasses with 6,400 NATO mils, 6,000 Warsaw Pact mils or 6,300 Swedish "streck" per turn instead of 360° or 2π radians, achieving higher resolution than a 360° compass while also being easier to divide into parts [...]"

I came across this angular unit when doing my Military Service back in the 80's. An Adjutant asked me to help him with his incoming exams for promotion to Sub Lieutenat, and upon inspecting the problems he needed to solve I noticed the angular unit "o/oo", called "milésimas". Never heard of it before, so I consulted his textbooks to get acquainted with this unit, as it was heavily used for artillery, to the exclusion of other angular units. See the following links:

Strich (Winkeleinheit) (in German)
Mil angulaire (in French)
Mil angular (in Spanish)

also see Milliradian (in English).

Sure enough, you can find o/oo used in many European armies, such as the Swiss Army, as you can see in this manual:

SHARP PC-1360 Schweizerische Armee TopoRechner

This is the Instruction Manual for a bundled system composed of a SHARP PC-1360 pocket computer, a 16 Kb RAM Card containing proprietary software. The software seems to deal with topographic calculations needed for the operation of Swiss Army's mobile artillery units back in 1986.

For example, in pp. 15-16 of the PDF, you can see the following inputs

Bereitstellungsazimut A o/oo
Seite A o/oo
Geländewinkel A o/oo
Azimut A o/oo

Should HP have released a model with the MIL angular mode, it would have been a real hit with the Military (pun intended), surely there's more of them than surveyors !

Best regards.
V.