[Octave-patch-tracker] [patch #9566] mapping package: ecc2n, n2ecc, majaxis, minaxis

[Philip Nienhuis]

Follow-up Comment #8, patch #9566 (project octave):

@Anonymous:
sorry for delay, busy times.

Code looks very good! thanks.
Only minor detail left is a period after the first help sentence (under the
function declarations in the header). FYI, when the documentation is extracted
from a function's texinfo header, there's a function
"get-first_help_sentence.m" (that does what its name suggests) that detects
where the first help sentence ends by looking for a.o., the period at the
end.
I'll take care of this and I'll push later after copyright updates, but
first:

...Another question about actual numbers:
What eccentricities are mentioned in the function headers for Earth?

In case of Earth radius:
Wikipedia (https://en.wikipedia.org/wiki/Earth_radius and
https://en.wikipedia.org/wiki/Flattening) and my own geology text books
indicate that Earth's major and minor semiaxes are ~6378 and 6356 km, resp. 
>From there I reckon that Earth's eccentricity (= first flattening) should be
0.0034494 (~1./289.91) rather than the value 0.081819221456 mentioned in the
ecc2n and n2ecc headers. The WGS84 geoid has an eccentricity of
1./298.257223563 = ~0.0033528.
In the function headers you mention Earth' eccentricity to be 0.081819221456,
i.e., around 24 times larger.

In case of Earth orbit:
The eccentricity of Earth' orbit currently is around 0.0167, or 10 times
larger than what's mentioned in the function headers (0.0016792).

==> So where did you get the values in the function headers from?


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